JP7318129B2 - Actinic ray-sensitive or radiation-sensitive resin composition, resist film, pattern forming method, electronic device manufacturing method - Google Patents

Description

TECHNICAL FIELD The present invention relates to an actinic ray-sensitive or radiation-sensitive resin composition, a resist film, a pattern forming method, and a compound for manufacturing an electronic device.

Since the resist for KrF excimer laser (248 nm), a pattern forming method using chemical amplification has been used in order to compensate for the sensitivity reduction due to light absorption. For example, in a positive chemical amplification method, first, a photoacid generator contained in an exposed area is decomposed by light irradiation to generate an acid. Then, in the post-exposure baking (PEB: Post Exposure Bake) process or the like, the alkali-insoluble groups of the resin contained in the actinic ray-sensitive or radiation-sensitive resin composition are converted into alkali-soluble groups by the catalytic action of the generated acid. The solubility in the developer is changed by, for example, changing the base. Thereafter, development is performed using, for example, a basic aqueous solution. Thereby, the exposed portion is removed to obtain a desired pattern.
For the miniaturization of semiconductor devices, the wavelength of the exposure light source is shortened and the numerical aperture (NA) of the projection lens is increased. Currently, an exposure machine using an ArF excimer laser with a wavelength of 193 nm as a light source has been developed. ing. Moreover, these days, the pattern formation method which uses extreme ultraviolet rays (EUV light: Extreme Ultraviolet) and an electron beam (EB: Electron Beam) as a light source is also being examined.
Under such circumstances, various structures have been proposed as actinic ray-sensitive or radiation-sensitive resin compositions.

For example, Patent Document 1 discloses an acid generator containing a salt represented by the following formula (I-114) as a component used in a resist composition.

JP 2019-24989 A

The present inventors investigated the resist composition described in Patent Document 1, and found that when the resist composition was used after being stored for a long period of time (for example, 3 months), the LWR (line width It was found that the roughness) performance may be inferior.

Accordingly, an object of the present invention is to provide an actinic ray- or radiation-sensitive resin composition capable of forming a pattern with excellent LWR performance even after long-term storage.
Another object of the present invention is to provide a resist film, a pattern forming method, and an electronic device manufacturing method related to the actinic ray-sensitive or radiation-sensitive resin composition.

The inventors have found that the above problems can be solved by the following configuration.

[1] containing a resin that decomposes under the action of an acid to increase its polarity, and a compound that generates an acid when exposed to actinic rays or radiation;
An actinic ray-sensitive or radiation-sensitive resin composition, wherein the compound that generates an acid upon exposure to actinic rays or radiation contains one or more of compounds (I) and (II) described later.
[2] The actinic ray-sensitive or radiation-sensitive resin composition according to [1], wherein the acid-decomposable group represents a group represented by formula (1) or (2) described later.
[3] The actinic ray-sensitive or radiation-sensitive resin composition according to [2], wherein the acid-decomposable group represents a group represented by formula (1).
[4] In the compound (I), at least one of the cation site M ₁ ⁺ and the cation site M ₂ ⁺ has the acid-decomposable group, and in the compound (II), the cation site M ₁ ⁺ The actinic ray-sensitive or radiation-sensitive resin composition according to any one of [1] to [3], at least one of which has the acid-decomposable group.
[5] The sensor according to any one of [1] to [4], wherein the anion site A ₂ ^- represents a structure represented by any one of formulas (BB-1) to (BB-3) described later. Actinic ray or radiation sensitive resin composition.
[6] The sensor according to any one of [1] to [5], wherein the anion site A ₁ ^- represents a structure represented by any of formulas (AA-1) and (AA-3) described below. Actinic ray or radiation sensitive resin composition.
[7] A resist film formed using the actinic ray-sensitive or radiation-sensitive resin composition according to any one of [1] to [6].
[8] forming a resist film on a substrate using the actinic ray-sensitive or radiation-sensitive resin composition according to any one of [1] to [6];
exposing the resist film;
and developing the exposed resist film using a developer.
[9] A method for manufacturing an electronic device, including the pattern forming method according to [8].

ADVANTAGE OF THE INVENTION According to this invention, the actinic-ray-sensitive or radiation-sensitive resin composition which can form the pattern which is excellent in LWR performance even after long-term storage can be provided.
In addition, the present invention can provide a resist film, a pattern forming method, and an electronic device manufacturing method related to the actinic ray-sensitive or radiation-sensitive resin composition.

The present invention will be described in detail below.
The description of the constituent elements described below may be made based on representative embodiments of the present invention, but the present invention is not limited to such embodiments.
Regarding the notation of a group (atomic group) in the present specification, as long as it does not contradict the spirit of the present invention, the notation that does not indicate substituted or unsubstituted includes both a group having no substituent and a group having a substituent. do. For example, an "alkyl group" includes not only an alkyl group having no substituent (unsubstituted alkyl group) but also an alkyl group having a substituent (substituted alkyl group). Also, the term "organic group" as used herein refers to a group containing at least one carbon atom.
The substituent is preferably a monovalent substituent unless otherwise specified.
The term "actinic rays" or "radiation" as used herein refers to, for example, the emission line spectrum of a mercury lamp, far ultraviolet rays represented by excimer lasers, extreme ultraviolet rays (EUV light: Extreme Ultraviolet), X-rays, and electron beams (EB : Electron Beam) and the like. As used herein, "light" means actinic rays or radiation.
Unless otherwise specified, the term "exposure" as used herein refers not only to exposure by the emission line spectrum of a mercury lamp, far ultraviolet rays represented by excimer lasers, extreme ultraviolet rays, X-rays, and EUV light, but also electron beams, and It also includes drawing with particle beams such as ion beams.
In the present specification, the term "~" is used to include the numerical values before and after it as lower and upper limits.
The bonding direction of the divalent groups described herein is not limited unless otherwise specified. For example, in the compound represented by the formula "XYZ", when Y is -COO-, Y may be -CO-O- or -O-CO- good too. Further, the above compound may be "X--CO--O--Z" or "X--O--CO--Z."

As used herein, (meth)acrylate refers to acrylate and methacrylate, and (meth)acryl refers to acrylic and methacrylic.
In this specification, the weight average molecular weight (Mw), number average molecular weight (Mn), and dispersity (also referred to as molecular weight distribution) (Mw/Mn) of the resin are measured using a GPC (Gel Permeation Chromatography) device (HLC-8120GPC manufactured by Tosoh Corporation). ) by GPC measurement (solvent: tetrahydrofuran, flow rate (sample injection volume): 10 μL, column: TSK gel Multipore HXL-M manufactured by Tosoh Corporation, column temperature: 40 ° C., flow rate: 1.0 mL / min, detector: differential refractive index It is defined as a polystyrene conversion value by a detector (Refractive Index Detector).

As used herein, the acid dissociation constant (pKa) represents the pKa in an aqueous solution. , is a calculated value. All pKa values described herein are calculated using this software package.

Software Package 1: Advanced Chemistry Development (ACD/Labs) Software V8.14 for Solaris (1994-2007 ACD/Labs).

On the other hand, pKa can also be obtained by molecular orbital calculation. As a specific method for this, there is a method of calculating the H 2 ⁺ dissociation free energy in an aqueous solution based on the thermodynamic cycle. H ⁺ dissociation free energy can be calculated by, for example, DFT (density functional theory), but various other methods have been reported in literature, etc., and are not limited to this. . Note that there are a plurality of software that can perform DFT, and Gaussian 16 is an example.

The pKa in the present specification refers to a value obtained by calculating a value based on a database of Hammett's substituent constants and known literature values using Software Package 1, as described above. If it cannot be calculated, a value obtained by Gaussian 16 based on DFT (Density Functional Theory) is adopted.
In addition, pKa in this specification refers to "pKa in aqueous solution" as described above, but when pKa in aqueous solution cannot be calculated, "pKa in dimethyl sulfoxide (DMSO) solution" is adopted. It shall be.

As used herein, halogen atoms include, for example, fluorine, chlorine, bromine, and iodine atoms.

[Actinic ray-sensitive or radiation-sensitive resin composition]
The actinic ray-sensitive or radiation-sensitive resin composition (hereinafter also referred to as "resist composition") of the present invention is characterized by a resin that is decomposed by the action of an acid to increase its polarity (hereinafter "acid-decomposable resin"). or “resin (A)”), and compounds (I) and (II) described later as compounds that generate acid upon exposure to actinic rays or radiation (hereinafter also simply referred to as “photoacid generators”). Any one or more of (hereinafter also referred to as "specific compound").
The resist composition of the present invention can form a pattern with excellent LWR due to the above structure even when used after being stored for a long period of time after production.
In the following, the presumed mechanism of action of the resist composition of the present invention will be described in comparison with the compounds disclosed in Patent Document 1.
The present inventors have now found that when the resist composition is stored for a long period of time after production, the acetal structure in the linking site linking the two anion sites of the compound disclosed in Patent Document 1 is cleaved by the action of acid. It was found that the LWR performance of the formed pattern deteriorated due to this. The acid is presumed to be generated by decomposition of the photoacid generator or decomposition of the resin during storage of the resist composition.
In contrast, the specific compound has a structure in which the linking site that links the anion sites and/or the linking site between the anion site and the structural site Z is not cleaved by the action of an acid (Condition IB, Condition IIB). , the LWR performance of the formed pattern is excellent even when the resist composition is used after being stored for a long period of time after production.
On the other hand, in the specific compound, the polar group is protected by a leaving group that leaves by the action of an acid at a position that does not cut the linking site connecting the anion sites or the linking site between the anion site and the structural site Z. It has an acid-decomposable group (hereinafter also referred to as "acid-decomposable group"). The acid-decomposable group in the specific compound can be decomposed by acid upon exposure to expose a polar group. That is, a resist film containing a specific compound can increase the solubility in an alkaline developer in the exposed region. As a result of this, the resist film has excellent dissolution contrast between exposed and unexposed areas and the pattern formed exhibits excellent LWR performance.
It is presumed that the synergy of the above mechanisms of action allows the resist composition of the present invention to form patterns with excellent LWR performance even when used after being stored for a long period of time after production.
In the following, even when the resist composition is used after being stored for a long period of time after production, the fact that a pattern with excellent LWR performance can be formed is also referred to as "excellent by the effect of the present invention".

The resist composition of the present invention will be described in detail below.
The resist composition may be a positive resist composition or a negative resist composition. Moreover, it may be a resist composition for alkali development or a resist composition for organic solvent development.
The resist composition is typically a chemically amplified resist composition.
First, the various components of the resist composition will be described in detail below.

[Photoacid generator]
The resist composition contains one or more compounds (specific compounds) selected from the group consisting of compounds (I) and (II) as compounds (photoacid generators) that generate acids upon exposure to actinic rays or radiation.
The resist composition may further contain a photoacid generator (hereinafter also referred to as "photoacid generator B") other than the specific compound, as described later.
First, the specific compounds (compounds (I) and (II)) are described below.

<Compound (I)>
Compound (I) has one or more of the following structural sites X and one or more of the following structural sites Y, and an acid-decomposable group in which a polar group is protected by a leaving group that leaves under the action of an acid. A compound that generates an acid containing the following first acidic site derived from the following structural site X and the following second acidic site derived from the following structural site Y when irradiated with an actinic ray or radiation. .
Structural site X: Structural site consisting of an anionic site A ₁ ⁻ and a cation site M ₁ ⁺ and forming a first acidic site represented by HA ₁ upon exposure to actinic rays or radiation Structural site Y: Anionic site A ₂ ⁻ and a cation site M ₂ ⁺ and a structural site that forms a second acidic site represented by HA ₂ upon exposure to actinic rays or radiation. meet.

Condition IA: A compound PI obtained by replacing the cation site M ₁ ⁺ in the structural site X and the cation site M ₂ ⁺ in the structural site Y in the compound (I) with H ⁺ is and the acid dissociation constant a1 derived from the acidic site represented by HA ₁ obtained by replacing the cation site M 1 ⁺ with H ⁺ , _and the cation site M ₂ ⁺ in the structural site Y with H ⁺ It has an acid dissociation constant a2 derived from the acidic site represented by _HA2 , and the acid dissociation constant a2 is greater than the acid dissociation constant a1.

Condition IA will be described in more detail below.
When the compound (I) is, for example, an acid-generating compound having one first acidic site derived from the structural site X and one second acidic site derived from the structural site Y , compound PI corresponds to "a compound having HA ₁ and HA ₂ ".
More specifically, the acid dissociation constant a1 and the acid dissociation constant a2 of the compound PI are such that when the acid dissociation constant of the compound PI is determined, the compound PI is "a compound having A ₁ ^- and HA ₂ is the acid dissociation constant a1, and the pKa when the above "compound having A ₁ ^- and HA ₂ " becomes "the compound having A ₁ ^- and A ₂ ^- " is the acid dissociation constant a2 be.

Further, the compound (I) is, for example, a compound that generates an acid having two first acidic sites derived from the structural site X and one second acidic site derived from the structural site Y. In some cases, compound PI is a "compound with two HA ₁ and one HA ₂ ".
When the acid dissociation constant of such compound PI is obtained, the acid dissociation constant when compound PI becomes "a compound having one A ₁ ^- , one HA ₁ and one HA ₂ ", and "1 The acid dissociation constant when "compound having two A ₁ ^- , one HA ₁ and one HA ₂ " becomes "compound having two A ₁ ^- and one HA ₂ " is the above acid dissociation constant It corresponds to a1. Also, the acid dissociation constant when "a compound having two A ₁ ^- and one HA ₂ -" becomes "a compound having two A ₁ ^- and A ₂ ^- " corresponds to the acid dissociation constant a2. That is, when there are a plurality of acid dissociation constants derived from the acidic site represented by HA ₁ obtained by replacing the cation site M ₁ ⁺ in the structural site X with H ⁺ as in such a compound PI, a plurality of acid dissociation constants are present. The value of the acid dissociation constant a2 is larger than the largest value among the acid dissociation constants a1 of . The acid dissociation constant when the compound PI becomes "a compound having one A ₁ ^- , one HA ₁ and one HA ₂ " is aa, and "one A ₁ ^- and one HA ₁ and 1 The relationship ^between aa and ab satisfies aa<ab, where ab is the acid dissociation constant when a compound having two _HA2 's becomes _a compound having two A1- and one _HA2 . .

The acid dissociation constant a1 and the acid dissociation constant a2 are determined by the method for measuring the acid dissociation constant described above.
The above compound PI corresponds to an acid generated when compound (I) is irradiated with actinic rays or radiation.
When compound (I) has two or more structural moieties X, each structural moiety X may be the same or different. Two or more of A ₁ ⁻ and two or more of M ₁ ⁺ may be the same or different.
In compound (I), A ₁ ⁻ and A ₂ ⁻ , and M ₁ ⁺ and M ₂ ⁺ may be the same or different, but A 1 ⁻ and A ₂ − may be the same or different. Each A ₂ ^- is preferably different.

The difference between the acid dissociation constant a1 (when there are multiple acid dissociation constants a1, the maximum value) and the acid dissociation constant a2 is 0.10 in terms of the LWR performance of the formed pattern being superior. is preferably 0.50 or more, more preferably 0.50 or more. The upper limit of the difference between the acid dissociation constant a1 (the maximum value if there are multiple acid dissociation constants a1) and the acid dissociation constant a2 is not particularly limited, but is, for example, 20.00 or less.

In addition, in the above compound PI, the acid dissociation constant a2 is, for example, 15.00 or less, preferably 12.00 or less, in that the LWR performance of the formed pattern is more excellent. The lower limit of the acid dissociation constant a2 is preferably -4.00 or more.

In addition, in the compound PI, the acid dissociation constant a1 is preferably 1.00 or less, more preferably 0.50 or less, from the viewpoint that the LWR performance of the formed pattern is more excellent. The lower limit of the acid dissociation constant a1 is preferably -12.00 or more.

^Condition IB: _The ^compound (I) has _a site ( hereinafter also referred to as “linking site”) is a structure that is not cleaved. The term "the linking site between the anion site A ₁ ^- and the anion site A ₂ ^- is not cleaved by the action of an acid" means that the anion site A ₁ ^- and the anion site A _{2 -} in compound (I) are separated by the action of an acid. It is intended that the linking site with ^- is not cleaved and the two are not separated. That is, when compound (I) is a compound represented by formula (Ia-1) described later, the linking group represented by L ₁ is intended to have a structure that is not cleaved by the action of an acid, and compound (I) is a compound represented by formula (Ia-1) described later. In the case of compounds represented by formulas (Ia-2) to (Ia-4), the linking groups represented by L ₂₁ , L ₂₂ , L ₃₁ , L ₃₂ and L ₄₁ are not cleaved by the action of acid. Intend structure.
The linking site that is cleaved by the action of an acid specifically includes a structure in which a polar group is protected by a leaving group that is released by the action of an acid, and the leaving group is eliminated by the action of an acid. Examples include organic linking groups whose linking sites can be cleaved by (including decomposition). For example, the compound disclosed in Patent Document 1 decomposes into a dihydroxy compound and a ketone compound when the acetal structural site connecting two anions is decomposed by the action of acid. In the compound (I), the linking site between the anion site A ₁ ^- and the anion site A ₂ ^- is located at a position where the linking site can be cleaved by elimination (including decomposition) of the leaving group by the action of an acid, It does not contain a structure in which a polar group is protected by a leaving group that leaves under the action of an acid. In the compound (I), the polar group is protected by a leaving group that leaves by the action of an acid at the linking site between the anion site A ₁ ^- and the anion site A ₂ ^- so as not to cleave the linking site. The structural group may be substituted. A structure in which a polar group is protected by a leaving group that leaves under the action of an acid will be described later together with the acid-decomposable group contained in the resin (A).

The anion site A ₁ ^- and the anion site A ₂ ^- are structural sites containing negatively charged atoms or atomic groups, for example, formulas (AA-1) to (AA-3) and formula (BB -1) to (BB-5). As the anion site A ₁ ^- , those capable of forming an acidic site with a small acid dissociation constant are preferable, and among them, the formulas (AA-1) to (AA-3) are preferable, and the formula (AA-1) and (AA-3) are more preferred. Further, the anion site A ₂ ^- is preferably one capable of forming an acidic site having a larger acid dissociation constant than the anion site A ₁ ^- , and among these, any one of the formulas (BB-1) to (BB-5) and more preferably any one of the formulas (BB-1) to (BB-3) from the viewpoint that the effects of the present invention are more excellent. In formulas (AA-1) to (AA-3) and formulas (BB-1) to (BB-5) below, * represents a bonding position. ^RA represents a monovalent organic group.

Moreover, the cation site M ₁ ⁺ and the cation site M ₂ ⁺ are structural sites containing positively charged atoms or atomic groups, and examples thereof include monovalent organic cations. Although the organic cation is not particularly limited, the same organic cations as those represented by M ₁₁ ⁺ and M ₁₂ ⁺ in formula (Ia-1) described later can be mentioned.

Compound (I) has an acid-decomposable group (hereinafter also referred to as "acid-decomposable group") in which a polar group is protected by a leaving group that is released by the action of an acid. In compound (I), the position of the acid-decomposable group is not particularly limited as long as it does not break the bond between the anion site A ₁ ^- in the structural site X and the anion site A ₂ ^- in the structural site Y. , the acid-decomposable group is preferably arranged in at least one of the cationic site M ₁ ⁺ and the cationic site M ₂ ⁺ in terms of better effects of the present invention.
The acid-decomposable group will be described later together with the acid-decomposable group contained in the resin (A), but among them, the acid-decomposable group represented by the following formula (1) or (2) is preferable.

In formula (1), R ₁₁ to R ₁₃ each independently represent an alkyl group, a cycloalkyl group, an alkenyl group, or an aryl group. The alkyl group and the alkenyl group may be linear or branched. Moreover, the cycloalkyl group and the aryl group may be either monocyclic or polycyclic.
Two of R ₁₁ to R ₁₃ may combine with each other to form a ring.
* represents the binding site.
When all of R ₁₁ to R ₁₃ are alkyl groups (linear or branched), at least two of R ₁₁ to R ₁₃ are preferably methyl groups.

As the alkyl group for R ₁₁ to R ₁₃ , an alkyl group having 1 to 4 carbon atoms is preferable.
Cycloalkyl groups for R ₁₁ to R ₁₃ include monocyclic cycloalkyl groups such as cyclopentyl and cyclohexyl groups, or polycyclic groups such as norbornyl, tetracyclodecanyl, tetracyclododecanyl and adamantyl groups. Ring cycloalkyl groups are preferred.
As the aryl group for R ₁₁ to R ₁₃ , an aryl group having 6 to 10 carbon atoms is preferable.
A vinyl group is preferred as the alkenyl group for R ₁₁ to R ₁₃ .
The cycloalkyl group formed by combining two of R ₁₁ to R ₁₃ may be either monocyclic or polycyclic. Single-membered cycloalkyl groups are more preferred. The cycloalkyl group formed by combining two of R ₁₁ to R ₁₃ includes, for example, a group in which one of the methylene groups constituting the ring has a heteroatom such as an oxygen atom, a heteroatom such as a carbonyl group, Alternatively, it may be substituted with a vinylidene group. In these cycloalkyl groups, one or more ethylene groups constituting the cycloalkane ring may be replaced with a vinylene group.

In addition, the alkyl group, cycloalkyl group, alkenyl group and aryl group represented by R ₁₁ to R ₁₃ may have a substituent. Examples of substituents include alkyl groups (1 to 4 carbon atoms), halogen atoms, hydroxyl groups, alkoxy groups (1 to 4 carbon atoms), carboxyl groups, and alkoxycarbonyl groups (2 to 6 carbon atoms). .

In formula (2), _R2 represents an alkyl group or a cycloalkyl group, and _R3 represents a hydrogen atom, an alkyl group, or a cycloalkyl group. The alkyl group and cycloalkyl group represented by R ₂ and R ₃ are synonymous with the alkyl group and cycloalkyl group represented by R ₁₁ , and the preferred embodiments are also the same.
In addition, R ₂ and R ₃ may combine with each other to form a ring. The ring formed by combining R ₂ and R ₃ may be either a monocyclic ring or a polycyclic ring, preferably a monocyclic ring, more preferably a 5- or 6-membered monocyclic ring. The ring is preferably an alicyclic ring.
* represents the binding site.

The acid-decomposable group is preferably introduced into compound (I) as, for example, a monovalent group represented by formula (1L) or formula (2L) below.
Formula (1L) *-LX-RX ₁
Formula (2L) *-LX-RX ₂
In formulas (1L) and (2L) above, LX represents a single bond or a divalent linking group.
The divalent linking group is not particularly limited, and examples thereof include -CO-, -O-, -SO-, -SO ₂ -, -S-, and alkylene groups (preferably having 1 to 6 carbon atoms. may be branched), a cycloalkylene group (preferably having 3 to 15 carbon atoms), a divalent aromatic hydrocarbon ring group (preferably a 6- to 10-membered ring, more preferably a 6-membered ring), and these A divalent linking group in which a plurality of groups are combined is exemplified.
In addition, the alkylene group, the cycloalkylene group, and the divalent aromatic hydrocarbon ring group may be substituted with a substituent. Substituents include, for example, halogen atoms (preferably fluorine atoms).
In formulas (1L) and (2L) above, RX ₁ represents an acid-decomposable group represented by formula (1) above, and RX ₂ represents an acid-decomposable group represented by formula (2) above. show.

Although the number of acid-decomposable groups possessed by compound (I) is not particularly limited, it is, for example, 1 to 10, preferably 1 to 9, more preferably 1 to 6.
Further, as described above, in compound (I), the acid-decomposable group is arranged at a position that does not cut the link between the anion site A ₁ ^- in the structural site X and the anion site A ₂ ^- in the structural site Y. Although it is not particularly limited, it is preferably arranged in at least one of the cation site M ₁ ⁺ and the cation site M ₂ ⁺ from the point of view that the effects of the present invention are more excellent. When an acid-labile group is located on at least one of the cationic site M ₁ ⁺ and the cationic site M ₂ ⁺ , it is preferred to have 1 to 3 acid-labile groups in one cationic site.

The specific structure of compound (I) is not particularly limited, but examples thereof include compounds represented by formulas (Ia-1) to (Ia-4) described below.
First, the compound represented by Formula (Ia-1) will be described below. The compounds represented by formula (Ia-1) are as follows.

M ₁₁ ⁺ A ₁₁ ^- - L ₁ - A ₁₂ ^- M ₁₂ ⁺ (Ia-1)

Compound (Ia-1) generates an acid represented by HA ₁₁ -L ₁ -A ₁₂ H upon exposure to actinic rays or radiation.

In formula (Ia-1), M ₁₁ ⁺ and M ₁₂ ⁺ each independently represent an organic cation.
A ₁₁ ^- and A ₁₂ ^- each independently represent a monovalent anionic functional group.
L ₁ represents a divalent linking group.
Each of M ₁₁ ⁺ and M ₁₂ ⁺ may be the same or different.
A ₁₁ ^- and A ₁₂ ^- may be the same or different, but are preferably different from each other.
However, in the compound PIa (HA ₁₁ -L ₁ -A ₁₂ H) obtained by replacing the organic cations represented by M ₁₁ ⁺ and M ₁₂ ⁺ with H ⁺ in the above formula (Ia-1), A ₁₂ H The acid dissociation constant a2 derived from the acidic site represented is greater than the acid dissociation constant a1 derived from the acidic site represented by _HA11 . The preferred values of the acid dissociation constant a1 and the acid dissociation constant a2 are as described above. Further, the compound PIa and the acid generated from the compound represented by the formula (Ia-1) upon exposure to actinic rays or radiation are the same.
At least one of M ₁₁ ⁺ , M ₁₂ ⁺ , A ₁₁ ⁻ , A ₁₂ ⁻ , and L ₁ has an acid-decomposable group as a substituent.
When at least one of A ₁₁ ⁻ , A ₁₂ ⁻ , and L ₁ has an acid-decomposable group as a substituent, organic compounds represented by M ₁₁ ⁺ and M ₁₂ ⁺ in formula (Ia-1) The cation is replaced with H ^{2 +} and the leaving group in the acid-decomposable group is replaced with a hydrogen atom (that is, in the case of the acid-decomposable group represented by formula (1) above, it becomes a carboxy group. ) in the compound, the acid dissociation constant derived from the site where the leaving group in the acid-decomposable group is replaced with a hydrogen atom is greater than the acid dissociation constant a2 derived from the acidic site represented by A ₁₂ H. preferable.

The organic cations represented by M ₁ ⁺ and M ₂ ⁺ in formula (Ia-1) are as described later.

The monovalent anionic functional group represented by A ₁₁ ^- intends a monovalent group containing the above-described anionic site A ₁ ^- . Further, the monovalent anionic functional group represented by A ₁₂ ^- is intended to be a monovalent group containing the above-described anion site A ₂ ^- .
The monovalent anionic functional groups represented by A ₁₁ ^- and A ₁₂ ^- include any of the above formulas (AA-1) to (AA-3) and formulas (BB-1) to (BB-5). It is preferably a monovalent anionic functional group containing an anion site, from the group consisting of formulas (AX-1) to (AX-3) and formulas (BX-1) to (BX-6) More preferably, it is a monovalent anionic functional group selected. Among the monovalent anionic functional groups represented by A ₁₁ ^- , monovalent anionic functional groups represented by any one of formulas (AX-1) to (AX-3) are preferred. More preferably, it is a monovalent anionic functional group represented by any one of formulas (AX-1) and (AX-3). Further, as the monovalent anionic functional group represented by A ₁₂ ^- , a monovalent anionic functional group represented by any one of formulas (BX-1) to (BX-6) is preferable. , is more preferably a monovalent anionic functional group represented by any one of the formulas (BX-1) to (BX-4) in that the effects of the present invention are more excellent.

In formulas (AX-1) to (AX-3), R ^A1 and R ^A2 each independently represent a monovalent organic group. * represents a binding position.

Examples of the monovalent organic group represented by R ^A1 include a cyano group, *—SO ₂ R ^A11 group, and *—COR ^A11 group.
R ^A11 is preferably an optionally substituted linear, branched or cyclic alkyl group.
The number of carbon atoms in the alkyl group is preferably 1-15, more preferably 1-10, even more preferably 1-6.
The above alkyl group may have a substituent. The substituent is preferably a monovalent group represented by formula (1L) or formula (2L), a fluorine atom, or a cyano group, more preferably a fluorine atom or a cyano group. When the alkyl group has a fluorine atom as a substituent, it may be a perfluoroalkyl group.

The monovalent organic group represented by ^RA2 is preferably a linear, branched or cyclic alkyl group or aryl group.
The number of carbon atoms in the alkyl group is preferably 1-15, more preferably 1-10, even more preferably 1-6.
The above alkyl group may have a substituent. The substituent is preferably a monovalent group represented by formula (1L) or formula (2L), a fluorine atom, or a cyano group, more preferably a fluorine atom or a cyano group. When the alkyl group has a fluorine atom as a substituent, it may be a perfluoroalkyl group.

The aryl group is preferably a phenyl group or a naphthyl group, more preferably a phenyl group.
The aryl group may have a substituent. Examples of substituents include monovalent groups represented by the above formula (1L) or formula (2L), fluorine atoms, iodine atoms, perfluoroalkyl groups (for example, preferably having 1 to 10 carbon atoms, preferably having 1 to 10 carbon atoms, 6 is more preferable), or a cyano group is preferable, and a fluorine atom, an iodine atom, a perfluoroalkyl group, or a cyano group is more preferable.

In formulas (B-1) to (B-6), R ^B represents a monovalent organic group. * represents a binding position.
The monovalent organic group represented by ^RB is preferably a linear, branched or cyclic alkyl group or aryl group.
The number of carbon atoms in the alkyl group is preferably 1-15, more preferably 1-10, even more preferably 1-6.
The above alkyl group may have a substituent. Although the substituent is not particularly limited, the substituent is preferably a monovalent group represented by the above formula (1L) or formula (2L), a fluorine atom, or a cyano group, more preferably a fluorine atom or a cyano group. . When the alkyl group has a fluorine atom as a substituent, it may be a perfluoroalkyl group.
In addition, the carbon atom that is the bonding position in the alkyl group (for example, in the case of formulas (BX-1) and (BX-4), the carbon atom directly bonded to -CO- indicated in the formula in the alkyl group corresponds However, in the case of formulas (BX-2) and (BX-3), the carbon atom directly bonded to -SO ₂ - specified in the formula in the alkyl group corresponds, and in the case of formula (BX-6), The carbon atom directly bonded to ^-N-- in the formula in the alkyl group) has a substituent, preferably a substituent other than a fluorine atom or a cyano group.
Moreover, the carbon atom of the alkyl group may be substituted with carbonyl carbon.

The aryl group is preferably a phenyl group or a naphthyl group, more preferably a phenyl group.
The aryl group may have a substituent. Examples of substituents include monovalent groups represented by the above formula (1L) or formula (2L), fluorine atoms, iodine atoms, perfluoroalkyl groups (for example, preferably having 1 to 10 carbon atoms, preferably having 1 to 10 carbon atoms, 6 is more preferable.), cyano group, alkyl group (eg, preferably having 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms.), alkoxy group (eg, preferably having 1 to 10 carbon atoms, 1 ~ 6 is more preferable.), or an alkoxycarbonyl group (e.g., preferably having 2 to 10 carbon atoms, more preferably having 2 to 6 carbon atoms.), a fluorine atom, an iodine atom, a perfluoroalkyl group, a cyano group, An alkyl group, an alkoxy group, or an alkoxycarbonyl group is more preferred.

In formula (I), the divalent linking group represented by L ₁ is not particularly limited, and includes -CO-, -NR-, -CO-, -O-, -S-, -SO-, -SO _2- , an alkylene group (preferably having 1 to 6 carbon atoms, which may be linear or branched), a cycloalkylene group (preferably having 3 to 15 carbon atoms), an alkenylene group (preferably having 2 to 6 carbon atoms), A divalent aliphatic heterocyclic group (preferably a 5- to 10-membered ring having at least one N atom, O atom, S atom, or Se atom in the ring structure, more preferably a 5- to 7-membered ring, 5-6 A membered ring is more preferable.), a divalent aromatic heterocyclic group (preferably a 5- to 10-membered ring having at least one N atom, O atom, S atom, or Se atom in the ring structure, 5- to 7-membered A ring is more preferable, and a 5- to 6-membered ring is more preferable.), a divalent aromatic hydrocarbon ring group (preferably a 6- to 10-membered ring, more preferably a 6-membered ring.), and a combination of a plurality of these A divalent linking group is mentioned. The above R includes a hydrogen atom or a monovalent organic group. Although the monovalent organic group is not particularly limited, for example, an alkyl group (preferably having 1 to 6 carbon atoms) is preferable.
Further, the alkylene group, the cycloalkylene group, the alkenylene group, the divalent aliphatic heterocyclic group, the divalent aromatic heterocyclic group, and the divalent aromatic hydrocarbon ring group are substituted with a substituent. may have been Examples of substituents include monovalent groups represented by the above formula (1L) or formula (2L), and halogen atoms (preferably fluorine atoms).

Among them, the divalent linking group represented by _L1 is preferably a divalent linking group represented by formula (L1).

In formula (L1), L ₁₁₁ represents a single bond or a divalent linking group.
The divalent linking group represented by L ₁₁₁ is not particularly limited, and examples include —CO—, —O—, —SO—, —SO ₂ —, an optionally substituted alkylene group (preferably is more preferably 1 to 6 carbon atoms (either linear or branched), a cycloalkylene group optionally having a substituent (preferably 3 to 15 carbon atoms), having a substituent an arylene group (preferably having 6 to 10 carbon atoms) which may be substituted, and a divalent linking group combining a plurality of these groups. The substituent is not particularly limited and includes, for example, a monovalent group represented by the above formula (1L) or formula (2L), a halogen atom, and the like.
p represents an integer of 0-3, preferably an integer of 1-3.
Each Xf ₁ independently represents a fluorine atom or an alkyl group substituted with at least one fluorine atom. The number of carbon atoms in this alkyl group is preferably 1-10, more preferably 1-4. A perfluoroalkyl group is preferable as the alkyl group substituted with at least one fluorine atom.
Each _Xf2 independently represents a hydrogen atom, an alkyl group optionally having a fluorine atom as a substituent, or a fluorine atom. The number of carbon atoms in this alkyl group is preferably 1-10, more preferably 1-4. _Xf2 preferably represents a fluorine atom or an alkyl group substituted with at least one fluorine atom, more preferably a fluorine atom or a perfluoroalkyl group.
Among them, Xf ₁ and Xf ₂ are each independently preferably a fluorine atom or a perfluoroalkyl group having 1 to 4 carbon atoms, more preferably a fluorine atom or CF ₃ . In particular, both Xf ₁ and Xf ₂ are more preferably fluorine atoms.
* represents a binding position.
When L ₁ in formula (Ia-1) represents a divalent linking group represented by formula (L1), the bond (*) on the L ₁₁₁ side in formula (L1) is represented by formula (Ia-1 ) is preferred to bind to A ₁₂ ⁻ in

Preferred forms of organic cations represented by M ₁₁ ⁺ and M ₁₂ ⁺ in formula (I) are described in detail.
The organic cations represented by M ₁₁ ⁺ and M ₁₂ ⁺ are each independently an organic cation represented by formula (ZaI) (cation (ZaI)) or an organic cation represented by formula (ZaII) (cation (ZaII )) is preferred.

In the above formula (ZaI),
R ²⁰¹ , R ²⁰² and R ²⁰³ each independently represent an organic group.
The number of carbon atoms in the organic groups as R ²⁰¹ , R ²⁰² and R ²⁰³ is generally 1-30, preferably 1-20. Also, two of R ²⁰¹ to R ²⁰³ may combine to form a ring structure, and the ring may contain an oxygen atom, a sulfur atom, an ester group, an amide group, or a carbonyl group. Examples of the group formed by combining two of R ²⁰¹ to R ²⁰³ include an alkylene group (eg, a butylene group and a pentylene group) and —CH ₂ —CH ₂ —O—CH ₂ —CH ₂ —. mentioned.

Preferred embodiments of the organic cation in formula (ZaI) include cation (ZaI-1), cation (ZaI-2), and organic cations represented by formula (ZaI-3b) (cation (ZaI-3b) ), and an organic cation represented by the formula (ZaI-4b) (cation (ZaI-4b)).

First, the cation (ZaI-1) will be described.
Cation (ZaI-1) is an arylsulfonium cation in which at least one of R ²⁰¹ to R ²⁰³ in formula (ZaI) above is an aryl group.
In the arylsulfonium cation, all of R ₂₀₁ to R ₂₀₃ may be aryl groups, or part of R ₂₀₁ to R ₂₀₃ may be aryl groups and the rest may be alkyl groups or cycloalkyl groups.
In addition, one of R ₂₀₁ to R ₂₀₃ may be an aryl group, and the remaining two of R ²⁰¹ to R ²⁰³ may combine to form a ring structure, in which an oxygen atom, a sulfur atom, It may contain an ester group, an amide group, or a carbonyl group. The group formed by bonding two of R ²⁰¹ to R ²⁰³ includes, for example, one or more methylene groups substituted with an oxygen atom, a sulfur atom, an ester group, an amide group and/or a carbonyl group. alkylene groups (eg, butylene group, pentylene group, or —CH ₂ —CH ₂ —O—CH ₂ —CH ₂ —).
Arylsulfonium cations include, for example, triarylsulfonium cations, diarylalkylsulfonium cations, aryldialkylsulfonium cations, diarylcycloalkylsulfonium cations, and aryldicycloalkylsulfonium cations.

The aryl group contained in the arylsulfonium cation is preferably a phenyl group or a naphthyl group, more preferably a phenyl group. The aryl group may be an aryl group having a heterocyclic structure having an oxygen atom, a nitrogen atom, a sulfur atom, or the like. Heterocyclic structures include pyrrole residues, furan residues, thiophene residues, indole residues, benzofuran residues, benzothiophene residues, and the like. When the arylsulfonium cation has two or more aryl groups, the two or more aryl groups may be the same or different.
The alkyl group or cycloalkyl group optionally possessed by the arylsulfonium cation is a linear alkyl group having 1 to 15 carbon atoms, a branched alkyl group having 3 to 15 carbon atoms, or 3 to 15 carbon atoms. is preferred, and for example, methyl group, ethyl group, propyl group, n-butyl group, sec-butyl group, t-butyl group, cyclopropyl group, cyclobutyl group, cyclohexyl group and the like are more preferred.

The substituents that the aryl group, alkyl group and cycloalkyl group of R ²⁰¹ to R ²⁰³ may have are each independently a monovalent group represented by the above formula (1L) or formula (2L). group (group containing an acid-decomposable group), alkyl group (eg, 1 to 15 carbon atoms), cycloalkyl group (eg, 3 to 15 carbon atoms), aryl group (eg, 6 to 14 carbon atoms), alkoxy group (eg, carbon 1 to 15), cycloalkylalkoxy groups (eg, 1 to 15 carbon atoms), halogen atoms (eg, fluorine, iodine), hydroxyl groups, carboxyl groups, ester groups, sulfinyl groups, sulfonyl groups, alkylthio groups, phenylthio groups, and the like. preferable.
The above substituent may further have a substituent if possible. For example, the above alkyl group may have a halogen atom as a substituent to form a halogenated alkyl group such as a trifluoromethyl group. .

Next, the cation (ZaI-2) will be explained.
Cation (ZaI-2) is a cation in which R ²⁰¹ to R ²⁰³ in formula (ZaI) each independently represents an organic group having no aromatic ring. Here, the aromatic ring also includes an aromatic ring containing a heteroatom.
The organic group having no aromatic ring as R ²⁰¹ to R ²⁰³ generally has 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms.
R ²⁰¹ to R ²⁰³ are each independently preferably an alkyl group, a cycloalkyl group, an allyl group or a vinyl group, and a linear or branched 2-oxoalkyl group, 2-oxocycloalkyl group or alkoxy A carbonylmethyl group is more preferred, and a linear or branched 2-oxoalkyl group is even more preferred.

Examples of alkyl groups and cycloalkyl groups represented by R ²⁰¹ to R ²⁰³ include linear alkyl groups having 1 to 10 carbon atoms or branched alkyl groups having 3 to 10 carbon atoms (eg, methyl, ethyl, propyl group, butyl group, and pentyl group), and cycloalkyl groups having 3 to 10 carbon atoms (eg, cyclopentyl group, cyclohexyl group, and norbornyl group).
R ²⁰¹ to R ²⁰³ are a monovalent group represented by formula (1L) or formula (2L) above, a halogen atom, an alkoxy group (eg, having 1 to 5 carbon atoms), a hydroxyl group, a cyano group, or a nitro group. It may be further substituted.

Next, the cation (ZaI-3b) will be explained.
The cation (ZaI-3b) is a cation represented by the following formula (ZaI-3b).

In formula (ZaI-3b),
R _1c to R _5c each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an alkylcarbonyloxy group, a cycloalkylcarbonyloxy group, a halogen atom, or a hydroxyl group , a nitro group, an alkylthio group, an arylthio group, or a monovalent group represented by the above formula (1L) or formula (2L).
R _6c and R _7c each independently represent a hydrogen atom, an alkyl group (such as a t-butyl group), a cycloalkyl group, a halogen atom, a cyano group, or an aryl group.
R _x and R _y each independently represent an alkyl group, a cycloalkyl group, a 2-oxoalkyl group, a 2-oxocycloalkyl group, an alkoxycarbonylalkyl group, an allyl group, or a vinyl group.

Any two or more of R _1c to R _5c , R _5c and R _6c , R _6c and R _7c , R _5c and R _x , and R _x and R _y may be bonded to each other to form a ring. The rings may each independently contain an oxygen atom, a sulfur atom, a ketone group, an ester bond, or an amide bond.
Examples of the ring include aromatic or non-aromatic hydrocarbon rings, aromatic or non-aromatic hetero rings, and polycyclic condensed rings in which two or more of these rings are combined. The ring includes a 3- to 10-membered ring, preferably a 4- to 8-membered ring, and more preferably a 5- or 6-membered ring.

Examples of groups formed by bonding two or more of R _1c to R _5c , R _6c and R _7c , and R _x and R _y include alkylene groups such as a butylene group and a pentylene group. A methylene group in this alkylene group may be substituted with a heteroatom such as an oxygen atom.
The group formed by combining R _5c and R _6c and R _5c and R _x is preferably a single bond or an alkylene group. The alkylene group includes a methylene group, an ethylene group, and the like.

R _1c to R _5c , R _6c , R _7c , R _x , R _y , and two or _more of R _1c to R 5c , R _5c and R _6c , R _6c and R _7c , R _5c and R _x , and the ring formed by combining R _x and R _y with each other may have a monovalent group represented by the above formula (1L) or formula (2L) as a substituent.

Next, the cation (ZaI-4b) will be explained.
The cation (ZaI-4b) is a cation represented by the following formula (ZaI-4b).

In formula (ZaI-4b),
l represents an integer of 0 to 2;
r represents an integer of 0 to 8;
R ₁₃ is a hydrogen atom, a halogen atom (e.g., fluorine atom, iodine atom, etc.), a hydroxyl group, an alkyl group, a halogenated alkyl group, an alkoxy group, a carboxyl group, an alkoxycarbonyl group, a group having a cycloalkyl group (cycloalkyl group may be itself, or may be a group partially containing a cycloalkyl group). These groups may have a substituent, and examples of the substituent include monovalent groups represented by the above formula (1L) or formula (2L).
Moreover, as one aspect of R ₁₃ , it is also preferable that it is a monovalent group represented by the above formula (1L) or formula (2L).
R ₁₄ is a hydroxyl group, a halogen atom (e.g., fluorine atom, iodine atom, etc.), an alkyl group, a halogenated alkyl group, an alkoxy group, an alkoxycarbonyl group, an alkylcarbonyl group, an alkylsulfonyl group, a cycloalkylsulfonyl group, or a cycloalkyl group (either a cycloalkyl group itself or a group partially containing a cycloalkyl group). These groups may have a substituent, and examples of the substituent include monovalent groups represented by the above formula (1L) or formula (2L). Each of R ₁₄ independently represents the above group such as a hydroxyl group when a plurality of R 14 are present.
Moreover, as one aspect of R ₁₄ , it is also preferable to be a monovalent group represented by the above formula (1L) or formula (2L).
Each R ₁₅ independently represents an alkyl group, a cycloalkyl group, or a naphthyl group. Two R ₁₅ may be joined together to form a ring. When two R ₁₅ are combined to form a ring, the ring skeleton may contain a heteroatom such as an oxygen atom or a nitrogen atom. In one aspect, two R ₁₅ are alkylene groups, preferably joined together to form a ring structure. The alkyl group, the cycloalkyl group, the naphthyl group, and the ring formed by bonding two R ₁₅ to each other may have a substituent. ) or a monovalent group represented by formula (2L).

In formula (ZaI-4b), the alkyl groups for R ₁₃ , R ₁₄ and R ₁₅ are preferably linear or branched. The number of carbon atoms in the alkyl group is preferably 1-10. As the alkyl group, a methyl group, an ethyl group, an n-butyl group, a t-butyl group, or the like is more preferable.

Next, formula (ZaII) will be described.
In formula (ZaII), R ²⁰⁴ and R ²⁰⁵ each independently represent an aryl group, an alkyl group or a cycloalkyl group.
The aryl group for R ²⁰⁴ and R ²⁰⁵ is preferably a phenyl group or a naphthyl group, more preferably a phenyl group. The aryl group for R ²⁰⁴ and R ²⁰⁵ may be an aryl group having a heterocyclic ring having an oxygen atom, a nitrogen atom, a sulfur atom, or the like. Skeletons of heterocyclic aryl groups include, for example, pyrrole, furan, thiophene, indole, benzofuran, and benzothiophene.
The alkyl group and cycloalkyl group for R ²⁰⁴ and R ²⁰⁵ include a linear alkyl group having 1 to 10 carbon atoms or a branched alkyl group having 3 to 10 carbon atoms (e.g., methyl group, ethyl group, propyl group, butyl group, or pentyl group), or a cycloalkyl group having 3 to 10 carbon atoms (eg, cyclopentyl group, cyclohexyl group, or norbornyl group).

The aryl group, alkyl group and cycloalkyl group of R ²⁰⁴ and R ²⁰⁵ may each independently have a substituent. Examples of substituents that the aryl group, alkyl group, and cycloalkyl group of R ²⁰⁴ and R ²⁰⁵ may have include a monovalent group represented by the above formula (1L) or formula (2L), an alkyl group (eg, 1 to 15 carbon atoms), a cycloalkyl group (eg, 3 to 15 carbon atoms), an aryl group (eg, 6 to 15 carbon atoms), an alkoxy group (eg, 1 to 15 carbon atoms), a halogen atom, a hydroxyl group, and a phenylthio group.

Next, Formulas (Ia-2) to (Ia-4) will be described.

In formula (Ia-2), A _21a ^- and A _21b ^- each independently represent a monovalent anionic functional group. Here, the monovalent anionic functional groups represented by A _21a ^- and A _21b ^- are meant to be monovalent groups containing the above-described anionic site A ₁ ^- . The monovalent anionic functional groups represented by A _21a ^- and A _21b ^- are not particularly limited, but are, for example, one or more selected from the group consisting of the above formulas (AX-1) to (AX-3). and the like.
A ₂₂ ^- represents a divalent anionic functional group. Here, the divalent anionic functional group represented by A ₂₂ ^- intends a divalent group containing the above-described anion site A ₂ ^- . Examples of the divalent anionic functional group represented by A ₂₂ ^- include divalent anionic functional groups represented by formulas (BX-7) to (BX-9) shown below.

M _21a ⁺ , M _21b ⁺ , and M ₂₂ ⁺ each independently represent an organic cation. The organic cations represented by M _21a ⁺ , M _21b ⁺ , and M ₂₂ ⁺ are synonymous with M ₁ ⁺ described above, and the preferred embodiments are also the same.
_L21 and _L22 each independently represent a divalent organic group.

Further, in the compound PIa-2 in which the organic cations represented by M _21a ⁺ , M _21b ⁺ , and M ₂₂ ⁺ _in the above formula (Ia-2) are replaced with H ⁺ , acidic The site-derived acid dissociation constant a2 is greater than the acid dissociation constant a1-1 derived from A _21a H and the acid dissociation constant a1-2 derived from the acidic site represented by A _21b H. The acid dissociation constant a1-1 and the acid dissociation constant a1-2 correspond to the acid dissociation constant a1 described above.
A _21a ^- and A _21b ^- may be the same or different. Moreover, M _21a ⁺ , M _21b ⁺ , and M ₂₂ ⁺ may be the same or different.
At least one of M _21a ⁺ , M _21b ⁺ , M ₂₂ ⁺ , A _21a ⁻ , A _21b ⁻ , A ₂₂ ⁻ , L ₂₁ and L ₂₂ has an acid-decomposable group as a substituent.
When at least one of A _21a ⁻ , A _21b ⁻ , A ₂₂ ⁻ , L ₂₁ and L ₂₂ has an acid-decomposable group as a substituent, M _21a ⁺ , M The organic cations represented by _21b ⁺ and M ₂₂ ⁺ are replaced with H ⁺ , and the leaving group in the acid-decomposable group is replaced with a hydrogen atom (that is, In the case of an acid-decomposable group, it becomes a carboxy group.) In the compound, the acid dissociation constant derived from the site formed by replacing the leaving group in the acid-decomposable group with a hydrogen atom is the acidic site represented by A ₂₂ H is preferably greater than the acid dissociation constant a2 derived from

In formula (Ia-3), A _31a ^- and A ₃₂ ^- each independently represent a monovalent anionic functional group. The definition of the monovalent anionic functional group represented by A _31a ^- is synonymous with A _21a ^- and A _21b ^- in formula (Ia-2) described above, and the preferred embodiments are also the same.
The monovalent anionic functional group represented by A ₃₂ ^- intends a monovalent group containing the anion site A ₂ ^- described above. Although the monovalent anionic functional group represented by A ₃₂ ^- is not particularly limited, for example, one or more monovalent anionic functional groups selected from the group consisting of the above formulas (BX-1) to (BX-6) One or more monovalent anionic functional groups selected from the group consisting of the above formulas (BX-1) to (BX-4) in that the effects of the present invention are more excellent. is preferred.
A _31b ^- represents a divalent anionic functional group. Here, the divalent anionic functional group represented by A _31b ^- intends a divalent group containing the above-mentioned anionic site A ₁ ^- . Examples of the divalent anionic functional group represented by A _31b ^- include divalent anionic functional groups represented by formula (AX-4) shown below.

M _31a ⁺ , M _31b ⁺ , and M ₃₂ ⁺ each independently represent a monovalent organic cation. The organic cations represented by M _31a ⁺ , M _31b ⁺ , and M ₃₂ ⁺ are synonymous with M ₁ ⁺ described above, and the preferred embodiments are also the same.
L ₃₁ and L ₃₂ each independently represent a divalent organic group.

Further, in the compound PIa-3 obtained by replacing the organic cations represented by M _31a ⁺ , M _31b ⁺ , and M ₃₂ ⁺ in the above formula (Ia-3) with H ⁺ , an acidic compound represented by A ₃₂ H The acid dissociation constant a2 derived from the site is greater than the acid dissociation constant a1-3 derived from the acidic site represented by A _31a H and the acid dissociation constant a1-4 derived from the acidic site represented by A _31b H. . The acid dissociation constant a1-3 and the acid dissociation constant a1-4 correspond to the acid dissociation constant a1 described above.
A _31a ^- and A ₃₂ ^- may be the same or different. In addition, M _31a ⁺ , M _31b ⁺ , and M ₃₂ ⁺ may be the same or different.
At least one of M _31a ⁺ , M _31b ⁺ , M ₃₂ ⁺ , A _31a ⁻ , A _31b ⁻ , A ₃₂ ⁻ , L ₃₁ and L ₃₂ has an acid-decomposable group as a substituent.
When at least one of A _31a ⁻ , A _31b ⁻ , A ₃₂ ⁻ , L ₃₁ and L ₃₂ has an acid-decomposable group as a substituent, M _31a ⁺ , M The organic cations represented by _31b ⁺ and M ₃₂ ⁺ are replaced with H ⁺ , and the leaving group in the acid-decomposable group is replaced with a hydrogen atom (that is, In the case of an acid-decomposable group, it becomes a carboxy group.) In the compound, the acid dissociation constant derived from the site formed by replacing the leaving group in the acid-decomposable group with a hydrogen atom is the acidic site represented by A ₃₂ H. is preferably greater than the acid dissociation constant a2 derived from

In formula (Ia-4), A _41a ⁻ , A _41b ⁻ , and A ₄₂ ⁻ each independently represent a monovalent anionic functional group. The definitions of the monovalent anionic functional groups represented by A _41a ^- and A _41b ^- are the same as those of A _21a ^- and A _21b ^- in formula (Ia-2) described above. The definition of the monovalent anionic functional group represented by A ₄₂ ^- is the same as A ₃₂ ^- in formula (Ia-3) described above, and the preferred embodiments are also the same.
M _41a ⁺ , M _41b ⁺ , and M ₄₂ ⁺ each independently represent an organic cation.
_L41 represents a trivalent organic group.

Further, in the compound PIa-4 obtained by replacing the organic cations represented by M _41a ⁺ , M _41b ⁺ , and M ₄₂ ⁺ in the above formula (Ia-4) with H ⁺ , an acidic compound represented by A ₄₂ H The acid dissociation constant a2 derived from the site is greater than the acid dissociation constant a1-5 derived from the acidic site represented by A _41a H and the acid dissociation constant a1-6 derived from the acidic site represented by A _41b H. . The acid dissociation constant a1-5 and the acid dissociation constant a1-6 correspond to the acid dissociation constant a1 described above.
A _41a ⁻ , A _41b ⁻ , and A ₄₂ ⁻ may be the same or different. In addition, M _41a ⁺ , M _41b ⁺ , and M ₄₂ ⁺ may be the same or different.
At least one of M _41a ⁺ , M _41b ⁺ , M ₄₂ ⁺ , A _41a ⁻ , A _41b ⁻ , A ₄₂ ⁻ , and L ₄₁ has an acid-decomposable group as a substituent.
When at least one of A _41a ⁻ , A _41b ⁻ , A ₄₂ ⁻ , and L ₄₁ has an acid-decomposable group as a substituent, M _41a ⁺ , M _41b ⁺ , The organic cation represented by M ₄₂ ⁺ is replaced with H ⁺ and the leaving group in the acid-decomposable group is replaced with a hydrogen atom (that is, the acid-decomposable group represented by the above formula (1) In the case of , it becomes a carboxy group.) In the compound, the acid dissociation constant derived from the site where the leaving group in the acid-decomposable group is replaced with a _hydrogen atom is the acid It is preferably larger than the dissociation constant a2.

The divalent organic groups represented by L ₂₁ and L ₂₂ in formula (Ia-2) and L ₃₁ and L ₃₂ in formula (Ia-3) are not particularly limited, for example, —CO— , —NR—, —O—, —S—, —SO—, —SO ₂ —, an alkylene group (preferably having 1 to 6 carbon atoms, which may be linear or branched), a cycloalkylene group (preferably 3 to 15 carbon atoms), alkenylene groups (preferably 2 to 6 carbon atoms), divalent aliphatic heterocyclic groups (at least one N atom, O atom, S atom, or Se atom in the ring structure 5 A to 10-membered ring is preferred, a 5- to 7-membered ring is more preferred, and a 5- to 6-membered ring is even more preferred.), a divalent aromatic heterocyclic group (at least one N atom, O atom, S atom, or Se A 5- to 10-membered ring having an atom in the ring structure is preferred, a 5- to 7-membered ring is more preferred, and a 5- to 6-membered ring is even more preferred.), a divalent aromatic hydrocarbon ring group (6- to 10-membered ring is preferred, and a 6-membered ring is more preferred.), and a divalent organic group combining a plurality of these. The above R includes a hydrogen atom or a monovalent organic group. Although the monovalent organic group is not particularly limited, for example, an alkyl group (preferably having 1 to 6 carbon atoms) is preferable.
Further, the alkylene group, the cycloalkylene group, the alkenylene group, the divalent aliphatic heterocyclic group, the divalent aromatic heterocyclic group, and the divalent aromatic hydrocarbon ring group are substituted with a substituent. may have been Examples of substituents include monovalent groups represented by the above formula (1L) or formula (2L), and halogen atoms (preferably fluorine atoms).

Examples of divalent organic groups represented by L ₂₁ and L ₂₂ in formula (Ia-2) and L ₃₁ and L ₃₂ in formula (Ia-3) are represented by the following formula (L2): It is also preferred that it is a divalent organic group that

In formula (L2), q represents an integer of 1-3. * represents a binding position.
Each Xf independently represents a fluorine atom or an alkyl group substituted with at least one fluorine atom. The number of carbon atoms in this alkyl group is preferably 1-10, more preferably 1-4. A perfluoroalkyl group is preferable as the alkyl group substituted with at least one fluorine atom.
Xf is preferably a fluorine atom or a C 1-4 perfluoroalkyl group, more preferably a fluorine atom or CF ₃ . In particular, it is more preferable that both Xf are fluorine atoms.

_LA represents a single bond or a divalent linking group.
The divalent linking group represented by L _A is not particularly limited, and examples thereof include -CO-, -O-, -SO-, -SO ₂ -, alkylene groups (preferably having 1 to 6 carbon atoms, straight-chain or branched), a cycloalkylene group (preferably having 3 to 15 carbon atoms), a divalent aromatic hydrocarbon ring group (preferably a 6- to 10-membered ring, more preferably a 6-membered ring), and Divalent linking groups in which a plurality of these are combined are included.
In addition, the alkylene group, the cycloalkylene group, and the divalent aromatic hydrocarbon ring group may be substituted with a substituent. Examples of substituents include monovalent groups represented by the above formula (1L) or formula (2L), and halogen atoms (preferably fluorine atoms).

Examples of the divalent organic group represented by formula (L2) include *-CF ₂ -*, *-CF ₂ -CF ₂ -*, *-CF ₂ -CF ₂ -CF ₂ -*, *- Ph-O- _SO2 - _CF2- *, *-Ph-O- _SO2 - _CF2 - _CF2- *, and *-Ph-O- _SO2 - _CF2 - _CF2 - _CF2- *, etc. Ph is an optionally substituted phenylene group, preferably a 1,4-phenylene group. Although the substituent is not particularly limited, for example, a monovalent group represented by the above formula (1L) or formula (2L), an alkyl group (for example, preferably having 1 to 10 carbon atoms, and having 1 to 6 carbon atoms, more preferably.), an alkoxy group (e.g., preferably having 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms.), or an alkoxycarbonyl group (e.g., preferably having 2 to 10 carbon atoms, and having 2 to 6 carbon atoms, is more preferred).
When L ₂₁ and L ₂₂ in formula (Ia-2) represent a divalent organic group represented by formula (L2), the bond (*) on the L _A side in formula (L2) is represented by formula ( It preferably binds to A ₂₂ ^- in Ia-2).
Further, when L ₃₂ in formula (Ia-3) represents a divalent organic group represented by formula (L2), the bond (*) on the L _A side in formula (L2) is represented by formula (Ia It is preferable to bind to A ₃₂ ^- in -3).

The trivalent organic group represented by L ₄₁ in formula (Ia-4) is not particularly limited, and examples thereof include trivalent organic groups represented by the following formula (L3).

In formula (L3), _LB represents a trivalent hydrocarbon ring group or a trivalent heterocyclic group. * represents a binding position.

The hydrocarbon ring group may be either an aromatic hydrocarbon ring group or an aliphatic hydrocarbon ring group. The number of carbon atoms contained in the hydrocarbon ring group is preferably 6-18, more preferably 6-14.
The heterocyclic group may be either an aromatic heterocyclic group or an aliphatic heterocyclic group. The heterocyclic ring is preferably a 5- to 10-membered ring having at least one N atom, O atom, S atom, or Se atom in the ring structure, more preferably a 5- to 7-membered ring, and a 5- to 6-membered ring. A ring is more preferred.
Among them, _LB is preferably a trivalent hydrocarbon ring group, more preferably a benzene ring group or an adamantane ring group. The benzene ring group or adamantane ring group may have a substituent. The substituents are not particularly limited, but include, for example, monovalent groups represented by the above formula (1L) or formula (2L), and halogen atoms (preferably fluorine atoms).

In formula (L3), L _B1 to L _B3 each independently represent a single bond or a divalent linking group. The divalent linking groups represented by L _B1 to L _B3 are not particularly limited, and examples thereof include —CO—, —NR—, —O—, —S—, —SO—, —SO ₂ —, and alkylene groups. (preferably having 1 to 6 carbon atoms, which may be linear or branched), cycloalkylene group (preferably having 3 to 15 carbon atoms), alkenylene group (preferably having 2 to 6 carbon atoms), divalent aliphatic Heterocyclic group (preferably a 5- to 10-membered ring having at least one N atom, O atom, S atom, or Se atom in the ring structure, more preferably a 5- to 7-membered ring, even more preferably a 5- to 6-membered ring ), a divalent aromatic heterocyclic group (preferably a 5- to 10-membered ring having at least one N atom, O atom, S atom, or Se atom in the ring structure, more preferably a 5- to 7-membered ring, A 5- to 6-membered ring is more preferred.), a divalent aromatic hydrocarbon ring group (preferably a 6- to 10-membered ring, more preferably a 6-membered ring.), and a divalent linking group combining a plurality of these. is mentioned. The above R includes a hydrogen atom or a monovalent organic group. Although the monovalent organic group is not particularly limited, for example, an alkyl group (preferably having 1 to 6 carbon atoms) is preferable.
Further, the alkylene group, the cycloalkylene group, the alkenylene group, the divalent aliphatic heterocyclic group, the divalent aromatic heterocyclic group, and the divalent aromatic hydrocarbon ring group are substituted with a substituent. may have been Examples of substituents include monovalent groups represented by the above formula (1L) or formula (2L), and halogen atoms (preferably fluorine atoms).
As the divalent linking group represented by L _B1 to L _B3 , among the above, —CO—, —NR—, —O—, —S—, —SO—, —SO ₂ —, substituents An optional alkylene group and a divalent linking group combining a plurality of these groups are preferred.

Divalent linking groups represented by L _B1 to L _B3 are more preferably divalent linking groups represented by formula (L3-1).

In formula (L3-1), L _B11 represents a single bond or a divalent linking group.
The divalent linking group represented by L _B11 is not particularly limited, and examples thereof include —CO—, —O—, —SO—, —SO ₂ —, an optionally substituted alkylene group (preferably has 1 to 6 carbon atoms and may be linear or branched), and a divalent linking group combining a plurality of these. The substituent is not particularly limited and includes, for example, a monovalent group represented by the above formula (1L) or formula (2L), a halogen atom, and the like.
r represents an integer of 1 to 3;
Xf has the same definition as Xf in formula (L2) described above, and the preferred embodiments are also the same.
* represents a binding position.

Examples of divalent linking groups represented by L _B1 to L _B3 include *-O-*, *-O-SO ₂ -CF ₂ -*, *-O-SO ₂ -CF ₂ -CF ₂ - *, *--O--SO ₂ --CF ₂ --CF ₂ --CF ₂ --*, *--COO--CH ₂ --CH ₂ --* and the like.
L ₄₁ in formula (Ia-4) contains a divalent organic group represented by formula (L3-1), and the divalent organic group represented by formula (L3-1) and A ₄₂ ⁻ is bound, the bond (*) on the carbon atom side shown in formula (L3-1) preferably binds to A ₄₂ ^— in formula (Ia-4).
Further, L ₄₁ in formula (Ia-4) contains a divalent organic group represented by formula (L3-1), and the divalent organic group represented by formula (L3-1) and A When _41a ^- and A _41b ^- are bonded, the bond (*) on the carbon atom side specified in formula (L3-1) is combined with A _41a ^- and A _41b ^- in formula (Ia-4). A combination is preferred.

<Compound (II)>
Compound (II) comprises an acid-decomposable group in which a polar group is protected by a leaving group that leaves under the action of an acid, two or more of the above structural moieties X, and one or more of the following structural moieties Z. and is a compound that generates an acid containing two or more of the first acidic sites derived from the structural site X and the structural site Z by irradiation with an actinic ray or radiation.
Structural site Z: nonionic site capable of neutralizing acid provided that compound (II) satisfies the following condition IIB.
Condition IIB: The compound (II) has a structure in which the site connecting the anion site A ₁ ^- in two or more structural sites X and the structural site Z is not cleaved by the action of an acid.
In addition, the intention and specific aspects of "the linking site is not decomposed by the action of acid" in Condition IIB are as explained in Condition IB. In the compound (II), the linking site between the anion sites A ₁ ^- and/or the linking position between the anion site A ₁ ^- and the structural site Z is such that the leaving group is eliminated (including decomposition) by the action of an acid. It does not contain a structure in which a polar group is protected by a leaving group that leaves by the action of an acid at a position where the linking site can be cleaved in . The phrase "the linking site is not decomposed by the action of an acid" means that, for example, when the compound (II) is a compound represented by the formula (IIa) described later, the linking groups represented by _L51 and _L52 are Structures that are not cleaved by the action of acid are intended.

The definition of structural site X and the definitions of A ₁ ^- and M ₁ ⁺ in compound (II) are the same as the definitions of structural site X and the definitions of A ₁ ^- and M ₁ ⁺ in compound (I) above. is synonymous with and preferred embodiments are also the same.

HA ₁ obtained by replacing the cation site M ₁ ⁺ in the structural site X with H ⁺ in the compound PII, which is obtained by replacing the cation site M ₁ ⁺ in the structural site X with H ⁺ in the compound (II). The preferred range of the acid dissociation constant a1 derived from the acidic site represented by is the same as the acid dissociation constant a1 in the above compound PI.
In addition, for example, when the compound (II) is a compound that generates an acid having two of the first acidic sites derived from the structural site X and the structural site Z, the compound PII is "two HA ₁ It corresponds to "a compound having When the acid dissociation constant of this compound PII is determined, the acid dissociation constant when the compound PII is "a compound having one A ₁ ^- and one HA ₁ " and "one A ₁ ^- and one HA The acid dissociation constant when the "compound having ₁ " becomes "the compound having two A ₁ ^- " corresponds to the acid dissociation constant a1.

The acid dissociation constant a1 is obtained by the method for measuring the acid dissociation constant described above.
The above compound PII corresponds to an acid generated when compound (II) is irradiated with actinic rays or radiation.
The two or more structural sites X may be the same or different. Two or more of A ₁ ⁻ and two or more of M ₁ ⁺ may be the same or different.

The acid-neutralizing nonionic site in structural site Z is not particularly limited, and for example, a site containing a group capable of electrostatically interacting with protons or a functional group having electrons is preferable. .
As a group capable of electrostatically interacting with protons or a functional group having electrons, a functional group having a macrocyclic structure such as a cyclic polyether, or a nitrogen atom having a lone pair of electrons that does not contribute to π conjugation is used. and functional groups possessed. A nitrogen atom having a lone pair of electrons that does not contribute to π-conjugation is, for example, a nitrogen atom having a partial structure represented by the following formula.

Partial structures of functional groups having electrons or groups capable of electrostatically interacting with protons include, for example, a crown ether structure, an azacrown ether structure, a primary to tertiary amine structure, a pyridine structure, an imidazole structure, and a pyrazine structure. etc., among which primary to tertiary amine structures are preferred.

Compound (II) has an acid-decomposable group in which a polar group is protected with a leaving group that leaves under the action of an acid. In compound (II), the type, number, and position of the acid-decomposable group are the same as the type, number, and position of the acid-decomposable group in compound (I), and preferred embodiments are also the same.

Compound (II) is not particularly limited, and examples thereof include compounds represented by the following formula (IIa).

In formula (IIa) above, A _51a ^- and A _51b ^- have the same meanings as A ₁₁ ^- in formula (Ia-1) above, and preferred embodiments are also the same. M _51a ⁺ and M _51b ⁺ have the same meanings as M ₁₁ ⁺ in formula (Ia-1) described above, and the preferred embodiments are also the same.
In formula (IIa) above, L ₅₁ and L ₅₂ each have the same meaning as L ₁ in formula (Ia-1) above, and the preferred embodiments are also the same.
When L ₅₁ in formula (IIa) represents a divalent linking group represented by formula (L1), the bond (*) on the L ₁₁₁ side in formula (L1) is is preferably attached to the nitrogen atom specified in . Further, when L ₅₂ in formula (IIa) represents a divalent linking group represented by formula (L1), the bond (*) on the L ₁₁₁ side in formula (L1) is is preferably attached to the nitrogen atom specified in .

In formula (IIa), R _2X represents a monovalent organic group. _The monovalent organic group represented by R _2X is not particularly limited _. - may be substituted with one or a combination of two or more selected from the group consisting of an alkyl group (preferably having 1 to 10 carbon atoms, which may be linear or branched), a cycloalkyl group (preferably includes 3 to 15 carbon atoms) or an alkenyl group (preferably 2 to 6 carbon atoms).
Moreover, the alkylene group, the cycloalkylene group, and the alkenylene group may be substituted with a substituent. Examples of substituents include, but are not limited to, monovalent groups represented by the above formula (1L) or formula (2L), and halogen atoms (preferably fluorine atoms).

Further, in the compound PIIa obtained by replacing the organic cations represented by M _51a ⁺ and M _51b ⁺ with H ⁺ in the above formula (IIa), the acid dissociation constant a1− derived from the acidic site represented by A _51a H The acid dissociation constants a1-8 derived from the acidic sites represented by 7 and A _51b H correspond to the acid dissociation constant a1 described above.
In the compound PIIa obtained by replacing the cationic site M ₁ ⁺ in the structural site X in the structural site X in the compound (IIa) with H ⁺ , HA _51a -L ₅₁ -N(R _2X )-L ₅₂ -A _51b H is Applicable. In addition, the compound PIIa and the acid generated from the compound represented by the formula (IIa) upon exposure to actinic rays or radiation are the same.
At least one of M _51a ⁺ , M _51b ⁺ , A _51a ⁻ , A _51b ⁻ , L ₅₁ , L ₅₂ and R _2X has an acid-decomposable group as a substituent.

The specific compound contained in the resist composition satisfies two or more of the following conditions (B1) to (B3) while satisfying the following condition (A) in that the effect of the present invention is more excellent (preferably, the following It is preferable to satisfy all of the following conditions (B1) to (B3) while satisfying the condition (A).
(A) The type of acid-decomposable group of the specific compound is the structure (ester structure) represented by formula (1) or the structure (acetal structure) represented by formula (2).
(B1) The type of acid-decomposable group of the specific compound is the structure (ester structure) represented by formula (1) described above.
(B2) In the specific compound, an acid-decomposable group is arranged at a cation site.
(B3) The specific compound corresponds to compound (I) described above, and the structure of the anion site A ₂ ^- corresponds to formulas (BB-1) to (BB-3) described above.

A specific compound may be used individually by 1 type, and may use 2 or more types.
When two or more specific compounds are used, at least one compound selected from the group consisting of the following compound (IA) and the following compound (II-A) (hereinafter, also referred to as compound (XA) ), and at least one compound selected from the group consisting of the following compound (IB) and the following compound (II-B) (hereinafter also referred to as compound (XB)), and and more preferably a combination of one or more of the following compounds (IA) and one or more of the following compounds (IB). This results in better defect performance.
Compound (IA): a compound corresponding to the above compound (I), having two or more structural moieties X and only one structural moiety Y Compound (IB): the above compound A compound corresponding to (I), having only one structural site X and having only one structural site Y Compound (II-A): A compound corresponding to the above compound (II) and a compound having three or more structural moieties X and only one structural moiety Z. Compound (II-B): A compound corresponding to the above compound (II) and having only two structural moieties X and having only one structural site Z

When the resist composition contains the compound (XA) and the compound (XB), the mass ratio of the content of the compound (XA) to the content of the compound (XB) (compound (XA) /Compound (XB)) is preferably 0.05 to 19.00, more preferably 0.18 to 5.67, even more preferably 0.43 to 2.33. If the mass ratio is within the above range, defect performance will be more excellent.

When the resist composition contains the compound (XA) and the compound (XB), while satisfying the above condition (A), the compound (X -A) and a compound (XB) that satisfies two or more of the above conditions (B1) to (B3) while satisfying the above condition (A). This results in better defect performance.

The specific compound preferably has a molecular weight of 300 to 5,000, more preferably 500 to 4,000, and even more preferably 700 to 3,000.

The content of the specific compound is preferably 0.1 to 80.0% by mass, more preferably 1.0 to 60.0% by mass, and 5.00 to 50.0% by mass relative to the total solid content of the composition. % is more preferred. In addition, solid content intends the component which forms a resist film, and does not include a solvent. In addition, as long as it is a component that forms a resist film, it is regarded as a solid content even if its property is liquid.
A specific compound may be used individually by 1 type, and may use 2 or more types. When two or more are used, the total content is preferably within the range of the preferred content.

Specific examples of specific compounds are illustrated below, but the present invention is not limited thereto.

<Photoacid generator (B)>
The resist composition may contain a photoacid generator (B). The photoacid generator (B) corresponds to a photoacid generator other than the specific compound described above.
The photoacid generator (B) may be in the form of a low-molecular-weight compound, or may be in the form of being incorporated into a part of the polymer. Moreover, the form of a low-molecular-weight compound and the form incorporated into a part of a polymer may be used in combination.
When the photoacid generator (B) is in the form of a low-molecular-weight compound, the molecular weight is preferably 3,000 or less, more preferably 2,000 or less, even more preferably 1,000 or less.
When the photoacid generator (B) is in the form of being incorporated in part of the polymer, it may be incorporated in part of the resin (A), or may be incorporated in a resin different from the resin (A). good.
In the present invention, the photoacid generator (B) is preferably in the form of a low molecular weight compound.

Examples of the photoacid generator (B) include compounds represented by “M ⁺ X ⁻ ” (onium salts), and compounds that generate an organic acid upon exposure are preferred.
Examples of the organic acid include sulfonic acid (aliphatic sulfonic acid, aromatic sulfonic acid, camphorsulfonic acid, etc.), carboxylic acid (aliphatic carboxylic acid, aromatic carboxylic acid, aralkyl carboxylic acid, etc.), carbonyl sulfonylimidic acid, bis(alkylsulfonyl)imidic acid, tris(alkylsulfonyl)methide acid and the like.

In the compound represented by "M ⁺ X ^- ", M ⁺ represents an organic cation.
The organic cation is preferably a cation represented by formula (ZaI) (cation (ZaI)) or a cation represented by formula (ZaII) (cation (ZaII)).
The cation represented by formula (ZaI) (cation (ZaI)) or the cation represented by formula (ZaII) (cation (ZaII)) is as described above.
As one embodiment, the organic cation represented by M ⁺ preferably has an acid-decomposable group. The acid-decomposable group includes the acid-decomposable group represented by formula (1) and the acid-decomposable group represented by formula (2).

In the compound represented by “M ⁺ X ⁻ ”, X ⁻ represents an organic anion.
The organic anion is not particularly limited, and is preferably a non-nucleophilic anion (an anion with remarkably low ability to cause a nucleophilic reaction).

Examples of non-nucleophilic anions include sulfonate anions (aliphatic sulfonate anions, aromatic sulfonate anions, camphorsulfonate anions, etc.), carboxylate anions (aliphatic carboxylate anions, aromatic carboxylate anions, , and aralkylcarboxylate anions), sulfonylimide anions, bis(alkylsulfonyl)imide anions, tris(alkylsulfonyl)methide anions, and the like.

The aliphatic moiety in the aliphatic sulfonate anion and the aliphatic carboxylate anion may be an alkyl group or a cycloalkyl group, a linear or branched alkyl group having 1 to 30 carbon atoms, or , a cycloalkyl group having 3 to 30 carbon atoms.
The alkyl group may be, for example, a fluoroalkyl group (which may or may not have a substituent other than a fluorine atom, and may be a perfluoroalkyl group).

The aryl group in the aromatic sulfonate anion and aromatic carboxylate anion is preferably an aryl group having 6 to 14 carbon atoms, such as a phenyl group, a tolyl group, and a naphthyl group.

The alkyl group, cycloalkyl group, and aryl group listed above may have a substituent. The substituent is not particularly limited, but specifically includes a nitro group, a halogen atom such as a fluorine atom or a chlorine atom, a carboxy group, a hydroxyl group, an amino group, a cyano group, an alkoxy group (preferably having 1 to 15 carbon atoms), an alkyl group (preferably having 1 to 10 carbon atoms), a cycloalkyl group (preferably having 3 to 15 carbon atoms), an aryl group (preferably having 6 to 14 carbon atoms), an alkoxycarbonyl group (preferably having 2 to 7 carbon atoms), Acyl group (preferably 2 to 12 carbon atoms), alkoxycarbonyloxy group (preferably 2 to 7 carbon atoms), alkylthio group (preferably 1 to 15 carbon atoms), alkylsulfonyl group (preferably 1 to 15 carbon atoms) , an alkyliminosulfonyl group (preferably having 1 to 15 carbon atoms), an aryloxysulfonyl group (preferably having 6 to 20 carbon atoms), and the like.

The aralkyl group in the aralkylcarboxylate anion is preferably an aralkyl group having 7 to 14 carbon atoms, such as benzyl, phenethyl, naphthylmethyl, naphthylethyl, and naphthylbutyl.

Sulfonylimide anions include, for example, saccharin anions.

As the alkyl group in the bis(alkylsulfonyl)imide anion and the tris(alkylsulfonyl)methide anion, an alkyl group having 1 to 5 carbon atoms is preferable. Substituents for these alkyl groups include halogen atoms, halogen-substituted alkyl groups, alkoxy groups, alkylthio groups, alkyloxysulfonyl groups, aryloxysulfonyl groups, and cycloalkylaryloxysulfonyl groups. Alkyl groups substituted by atoms or fluorine atoms are preferred.
In addition, the alkyl groups in the bis(alkylsulfonyl)imide anion may combine with each other to form a ring structure. This increases the acid strength.

Examples of non-nucleophilic anions include aliphatic sulfonate anions in which at least the α-position of sulfonic acid is substituted with fluorine atoms, aromatic sulfonate anions in which fluorine atoms or groups having fluorine atoms are substituted, and alkyl groups in which fluorine atoms are present. A bis(alkylsulfonyl)imide anion substituted with or a tris(alkylsulfonyl)methide anion in which an alkyl group is substituted with a fluorine atom is preferable.

Examples of the photoacid generator (B) include, for example, paragraphs [0135] to [0171] of WO2018/193954, paragraphs [0077] to [0116] of WO2020/066824, WO2017/ It is also preferable to use the photoacid generators disclosed in paragraphs [0018] to [0075] and [0334] to [0335] of JP-A-154345.

When the resist composition contains the photoacid generator (B), its content is not particularly limited, but is preferably 0.5% by mass or more, more preferably 1% by mass or more, based on the total solid content of the composition. preferable. The content is preferably 30% by mass or less, more preferably 25% by mass or less, still more preferably 15% by mass or less, and particularly preferably 10% by mass or less.
The photoacid generator (B) may be used alone or in combination of two or more. When two or more are used, the total content is preferably within the range of the preferred content.

[Acid-decomposable resin (resin (A))]
The resist composition contains a resin that is decomposed by the action of an acid to increase its polarity (also referred to as "acid-decomposable resin" or "resin (A)").
That is, in the pattern forming method of the present invention, typically, when an alkaline developer is used as the developer, a positive pattern is preferably formed, and when an organic developer is used as the developer, the positive pattern is preferably formed. , a negative pattern is preferably formed.
The resin (A) usually contains a group that is decomposed by the action of an acid to increase its polarity (hereinafter also referred to as "acid-decomposable group"), and preferably contains a repeating unit having an acid-decomposable group.
As the repeating unit having an acid-decomposable group, in addition to the repeating unit having an acid-decomposable group described later, the repeating unit having an acid-decomposable group containing an unsaturated bond described later is preferable.

<Repeating unit having an acid-decomposable group>
An acid-decomposable group is a group that is decomposed by the action of an acid to form a polar group. The acid-decomposable group preferably has a structure in which the polar group is protected with a leaving group that leaves under the action of an acid. That is, the resin (A) has a repeating unit having a group that is decomposed by the action of an acid to form a polar group. A resin having this repeating unit has an increased polarity under the action of an acid, thereby increasing the solubility in an alkaline developer and decreasing the solubility in an organic solvent.
In the following, after describing the acid-decomposable group, the repeating unit having an acid-decomposable group will be described. The acid-decomposable group described below can also be applied as an acid-decomposable group possessed by the specific compound described above. In addition, in the specific compound, the linking site is cleaved by the action of an acid in the linking site between the anion sites and/or in the linking site between the anion site and the structural site Z. It does not contain a structure in which a polar group is protected with a leaving group that leaves by the action of an acid at a possible position.
As described above, the repeating unit having an acid-decomposable group is preferably the repeating unit having an acid-decomposable group (repeating unit having an acid-decomposable group), as well as the repeating unit having an acid-decomposable group containing an unsaturated bond. .

(Acid-decomposable group)
An acid-decomposable group is a group that is decomposed by the action of an acid to form a polar group. The acid-decomposable group preferably has a structure in which the polar group is protected with a leaving group that leaves under the action of an acid. An acid-decomposable group can be decomposed by the action of an acid to produce a polar group.
The polar group is preferably an alkali-soluble group such as a carboxyl group, a phenolic hydroxyl group, a fluorinated alcohol group, a sulfonic acid group, a phosphoric acid group, a sulfonamide group, a sulfonylimide group, (alkylsulfonyl)(alkylcarbonyl)methylene group, (alkylsulfonyl)(alkylcarbonyl)imide group, bis(alkylcarbonyl)methylene group, bis(alkylcarbonyl)imide group, bis(alkylsulfonyl)methylene group, bis(alkylsulfonyl)imide group, tris(alkylcarbonyl) Methylene group, acidic group such as tris(alkylsulfonyl)methylene group, and alcoholic hydroxyl group.
Among them, the polar group is preferably a carboxyl group, a phenolic hydroxyl group, a fluorinated alcohol group (preferably a hexafluoroisopropanol group), or a sulfonic acid group.

Examples of the leaving group that leaves by the action of an acid include groups represented by formulas (Y1) to (Y4).
Formula (Y1): -C(Rx ₁ )(Rx ₂ )(Rx ₃ )
Formula (Y2): -C(=O)OC(Rx ₁ )(Rx ₂ )(Rx ₃ )
Formula (Y3): —C(R ₃₆ )(R ₃₇ )(OR ₃₈ )
Formula (Y4): -C(Rn)(H)(Ar)

In formula (Y1) and formula (Y2), each of Rx ₁ to Rx ₃ is independently an alkyl group (linear or branched), a cycloalkyl group (monocyclic or polycyclic), an alkenyl group (linear or branched chain), or an aryl group (monocyclic or polycyclic). When all of Rx ₁ to Rx ₃ are alkyl groups (linear or branched), at least two of Rx ₁ to Rx ₃ are preferably methyl groups.
Among them, Rx ₁ to Rx ₃ preferably each independently represent a linear or branched alkyl group, and Rx ₁ to Rx ₃ each independently represent a linear alkyl group. is more preferred.
Two of Rx ₁ to Rx ₃ may combine to form a monocyclic or polycyclic ring.
The alkyl group of Rx ₁ to Rx ₃ is preferably an alkyl group having 1 to 5 carbon atoms such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group and t-butyl group. .
The cycloalkyl groups represented by Rx ₁ to Rx ₃ include monocyclic cycloalkyl groups such as cyclopentyl and cyclohexyl groups, and polycyclic groups such as norbornyl, tetracyclodecanyl, tetracyclododecanyl and adamantyl groups. is preferred.
The aryl group represented by Rx ₁ to Rx ₃ is preferably an aryl group having 6 to 10 carbon atoms, such as phenyl group, naphthyl group and anthryl group.
A vinyl group is preferable as the alkenyl group for Rx ₁ to Rx ₃ .
The ring formed by combining two of Rx ₁ to Rx ₃ is preferably a cycloalkyl group. The cycloalkyl group formed by combining two of Rx ₁ to Rx ₃ includes a monocyclic cycloalkyl group such as a cyclopentyl group or a cyclohexyl group, a norbornyl group, a tetracyclodecanyl group, and a tetracyclododecanyl group. or a polycyclic cycloalkyl group such as an adamantyl group, and more preferably a monocyclic cycloalkyl group having 5 to 6 carbon atoms.
The cycloalkyl group formed by combining two of Rx ₁ to Rx ₃ is, for example, a group in which one of the methylene groups constituting the ring has a heteroatom such as an oxygen atom, a heteroatom such as a carbonyl group, or a vinylidene group may be substituted. In these cycloalkyl groups, one or more ethylene groups constituting the cycloalkane ring may be replaced with a vinylene group.
In the group represented by formula (Y1) or formula (Y2), for example, Rx ₁ is a methyl group or an ethyl group, and Rx ₂ and Rx ₃ combine to form the above-described cycloalkyl group. is preferred.
For example, when the resist composition is a resist composition for EUV exposure, two of alkyl groups, cycloalkyl groups, alkenyl groups, aryl groups, and Rx ₁ to Rx ₃ represented by Rx ₁ to Rx ₃ are bonded The ring formed by the above preferably further has a fluorine atom or an iodine atom as a substituent.

In formula (Y3), R ₃₆ to R ₃₈ each independently represent a hydrogen atom or a monovalent organic group. R ₃₇ and R ₃₈ may combine with each other to form a ring. Monovalent organic groups include alkyl groups, cycloalkyl groups, aryl groups, aralkyl groups, alkenyl groups, and the like. It is also preferred that R ₃₆ is a hydrogen atom.
The alkyl group, cycloalkyl group, aryl group, and aralkyl group may contain a heteroatom such as an oxygen atom and/or a group having a heteroatom such as a carbonyl group. For example, in the alkyl group, cycloalkyl group, aryl group, and aralkyl group, one or more methylene groups are replaced with a heteroatom such as an oxygen atom and/or a group having a heteroatom such as a carbonyl group. good too.
In addition, in the repeating unit having an acid-decomposable group, which will be described later, R ₃₈ may combine with another substituent of the main chain of the repeating unit to form a ring. The group formed by bonding R ₃₈ and another substituent of the main chain of the repeating unit to each other is preferably an alkylene group such as a methylene group.
When the resist composition is, for example, a resist composition for EUV exposure, the monovalent organic groups represented by R ₃₆ to R ₃₈ and the ring formed by combining R ₃₇ and R ₃₈ with each other are Furthermore, it is also preferable to have a fluorine atom or an iodine atom as a substituent.

As the formula (Y3), a group represented by the following formula (Y3-1) is preferable.

Here, L ₁ and L ₂ each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, or a group combining these (for example, a group combining an alkyl group and an aryl group).
M represents a single bond or a divalent linking group.
Q is an alkyl group optionally containing a heteroatom, a cycloalkyl group optionally containing a heteroatom, an aryl group optionally containing a heteroatom, an amino group, an ammonium group, a mercapto group, a cyano group, an aldehyde group, or a group in which these are combined (for example, a group in which an alkyl group and a cycloalkyl group are combined).
Alkyl and cycloalkyl groups may, for example, have one of the methylene groups replaced by a heteroatom such as an oxygen atom or a heteroatom-bearing group such as a carbonyl group.
One of L ₁ and L ₂ is preferably a hydrogen atom, and the other is preferably an alkyl group, a cycloalkyl group, an aryl group, or a combination of an alkylene group and an aryl group.
At least two of Q, M, and _L1 may combine to form a ring (preferably a 5- or 6-membered ring).
From the viewpoint of pattern refinement, _L2 is preferably a secondary or tertiary alkyl group, more preferably a tertiary alkyl group. Secondary alkyl groups include isopropyl, cyclohexyl and norbornyl groups, and tertiary alkyl groups include tert-butyl and adamantane groups. In these embodiments, the Tg (glass transition temperature) and activation energy of the resin (A) are increased in the repeating unit having an acid-decomposable group, which will be described later. can.

When the resist composition is, for example, a resist composition for EUV exposure, the alkyl group, cycloalkyl group, aryl group, and group combining these represented by L ₁ and L ₂ may further have , a fluorine atom or an iodine atom. In addition, the above alkyl group, cycloalkyl group, aryl group, and aralkyl group contain a heteroatom such as an oxygen atom in addition to the fluorine atom and the iodine atom (that is, the above alkyl group, cycloalkyl group , aryl groups, and aralkyl groups, for example, one of the methylene groups is replaced by a heteroatom such as an oxygen atom, or a group containing a heteroatom such as a carbonyl group.
Further, when the resist composition is, for example, a resist composition for EUV exposure, an alkyl group which may contain a heteroatom represented by Q, a cycloalkyl group which may contain a heteroatom, a heteroatom, In the aryl group, amino group, ammonium group, mercapto group, cyano group, aldehyde group, and groups that are a combination thereof, the heteroatom is selected from the group consisting of a fluorine atom, an iodine atom and an oxygen atom. It is also preferred that the heteroatom is

In formula (Y4), Ar represents an aromatic ring group. Rn represents an alkyl group, a cycloalkyl group, or an aryl group. Rn and Ar may combine with each other to form a non-aromatic ring. Ar is more preferably an aryl group.
For example, when the resist composition is an EUV exposure resist composition, the aromatic ring group represented by Ar and the alkyl group, cycloalkyl group, and aryl group represented by Rn have fluorine atoms as substituents. and an iodine atom.

In terms of further improving acid decomposability, when a non-aromatic ring is directly bonded to a polar group (or a residue thereof) in a leaving group that protects a polar group, the polar It is also preferred that the ring member atoms adjacent to the ring member atom directly bonded to the group (or residue thereof) do not have halogen atoms such as fluorine atoms as substituents.

The leaving group that leaves by the action of an acid is also a 2-cyclopentenyl group having a substituent (such as an alkyl group) such as a 3-methyl-2-cyclopentenyl group, and a 1,1,4, A cyclohexyl group having a substituent (such as an alkyl group) such as a 4-tetramethylcyclohexyl group may also be used.

(Repeating unit containing an acid-decomposable group)
Next, the repeating unit having an acid-decomposable group that the resin (A) may contain will be described.
As the repeating unit having an acid-decomposable group, in addition to the above-described repeating unit having an acid-decomposable group, a repeating unit represented by formula (A) shown below is also preferable.

L ₁ represents a divalent linking group optionally having a fluorine atom or an iodine atom, and R ₁ is a hydrogen atom, a fluorine atom, an iodine atom, an alkyl group optionally having a fluorine atom or an iodine atom , or represents an aryl group optionally having a fluorine atom or an iodine atom, and R ₂ represents a leaving group optionally having a fluorine atom or an iodine atom which is eliminated by the action of an acid. However, at least one of L ₁ , R ₁ and R ₂ has a fluorine atom or an iodine atom.
L ₁ represents a divalent linking group optionally having a fluorine atom or an iodine atom. The divalent linking group optionally having a fluorine atom or an iodine atom includes —CO—, —O—, —S—, —SO—, —SO ₂ —, a fluorine atom or an iodine atom. may be a hydrocarbon group (eg, an alkylene group, a cycloalkylene group, an alkenylene group, an arylene group, etc.), a linking group in which a plurality of these are linked, and the like. Among them, L ₁ is preferably -CO-, arylene group, or -arylene group - alkylene group having fluorine atom or iodine atom -, -CO- or -arylene group - alkylene having fluorine atom or iodine atom Group - is more preferred.
A phenylene group is preferred as the arylene group.
Alkylene groups may be linear or branched. Although the number of carbon atoms in the alkylene group is not particularly limited, it is preferably 1-10, more preferably 1-3.
The total number of fluorine atoms and iodine atoms contained in the alkylene group having fluorine atoms or iodine atoms is not particularly limited, but is preferably 2 or more, more preferably 2 to 10, and even more preferably 3 to 6.

R ₁ represents a hydrogen atom, a fluorine atom, an iodine atom, an alkyl group optionally having a fluorine atom or an iodine atom, or an aryl group optionally having a fluorine atom or an iodine atom.
Alkyl groups may be straight or branched. Although the number of carbon atoms in the alkyl group is not particularly limited, it is preferably 1-10, more preferably 1-3.
The total number of fluorine atoms and iodine atoms contained in the alkyl group having fluorine atoms or iodine atoms is not particularly limited, but is preferably 1 or more, more preferably 1 to 5, and even more preferably 1 to 3.
The above alkyl group may contain a heteroatom such as an oxygen atom other than the halogen atom.

R ₂ represents a leaving group that leaves by the action of an acid and may have a fluorine atom or an iodine atom. The leaving group which may have a fluorine atom or an iodine atom includes the leaving groups represented by the above formulas (Y1) to (Y4) and having a fluorine atom or an iodine atom, and preferred embodiments are also the same. is.

Moreover, as the repeating unit having an acid-decomposable group, a repeating unit represented by formula (AI) is also preferable.

In formula (AI),
Xa ₁ represents a hydrogen atom or an optionally substituted alkyl group.
T represents a single bond or a divalent linking group.
Rx ₁ to Rx ₃ each independently represent an alkyl group (linear or branched), a cycloalkyl group (monocyclic or polycyclic), an alkenyl group (linear or branched), or an aryl ( monocyclic or polycyclic) group. However, when all of Rx ₁ to Rx ₃ are alkyl groups (linear or branched), at least two of Rx ₁ to Rx ₃ are preferably methyl groups.
Two of Rx ₁ to Rx ₃ may combine to form a monocyclic or polycyclic ring (such as a monocyclic or polycyclic cycloalkyl group).

Examples of the optionally substituted alkyl group represented by Xa ₁ include a methyl group and a group represented by -CH ₂ -R ₁₁ . R ₁₁ represents a halogen atom (such as a fluorine atom), a hydroxyl group, or a monovalent organic group, for example, an alkyl group having 5 or less carbon atoms which may be substituted with a halogen atom, or an alkyl group which may be substituted with a halogen atom Examples include acyl groups having 5 or less carbon atoms and alkoxy groups having 5 or less carbon atoms which may be substituted with halogen atoms, preferably alkyl groups having 3 or less carbon atoms, and more preferably methyl groups. Xa ₁ is preferably a hydrogen atom, a methyl group, a trifluoromethyl group, or a hydroxymethyl group.

The divalent linking group of T includes an alkylene group, an aromatic ring group, a --COO--Rt-- group, an --O--Rt-- group and the like. In the formula, Rt represents an alkylene group or a cycloalkylene group.
T is preferably a single bond or a -COO-Rt- group. When T represents a -COO-Rt- group, Rt is preferably an alkylene group having 1 to 5 carbon atoms, a -CH ₂ - group, a -(CH ₂ ) ₂ - group, or a -(CH ₂ ) ₃ - group is more preferred.

The alkyl group for Rx ₁ to Rx ₃ is preferably an alkyl group having 1 to 4 carbon atoms such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group and t-butyl group. .
The cycloalkyl groups represented by Rx ₁ to Rx ₃ include monocyclic cycloalkyl groups such as cyclopentyl and cyclohexyl groups, or polycyclic groups such as norbornyl, tetracyclodecanyl, tetracyclododecanyl and adamantyl groups. is preferred.
The aryl group represented by Rx ₁ to Rx ₃ is preferably an aryl group having 6 to 10 carbon atoms, such as phenyl group, naphthyl group and anthryl group.
A vinyl group is preferable as the alkenyl group for Rx ₁ to Rx ₃ .
The cycloalkyl group formed by combining two of Rx ₁ to Rx ₃ is preferably a monocyclic cycloalkyl group such as a cyclopentyl group and a cyclohexyl group, and also a norbornyl group, a tetracyclodecanyl group, Polycyclic cycloalkyl groups such as a tetracyclododecanyl group and an adamantyl group are preferred. Among them, monocyclic cycloalkyl groups having 5 to 6 carbon atoms are preferred.
The cycloalkyl group formed by combining two of Rx ₁ to Rx ₃ is, for example, a group in which one of the methylene groups constituting the ring has a heteroatom such as an oxygen atom, a heteroatom such as a carbonyl group, or a vinylidene group may be substituted. In these cycloalkyl groups, one or more ethylene groups constituting the cycloalkane ring may be replaced with a vinylene group.
In the repeating unit represented by formula (AI), for example, Rx ₁ is a methyl group or an ethyl group, and Rx ₂ and Rx ₃ are preferably combined to form the above-mentioned cycloalkyl group.

When each of the above groups has a substituent, examples of the substituent include an alkyl group (having 1 to 4 carbon atoms), a halogen atom, a hydroxyl group, an alkoxy group (having 1 to 4 carbon atoms), a carboxyl group, and an alkoxycarbonyl group ( 2 to 6 carbon atoms) and the like. The number of carbon atoms in the substituent is preferably 8 or less.

The repeating unit represented by formula (AI) is preferably an acid-decomposable (meth)acrylic acid tertiary alkyl ester-based repeating unit (Xa ₁ represents a hydrogen atom or a methyl group, and T represents a single bond It is a repeating unit that represents

The content of repeating units having an acid-decomposable group is preferably 15 mol % or more, more preferably 20 mol % or more, and still more preferably 30 mol % or more, based on all repeating units in the resin (A). The upper limit is preferably 90 mol % or less, more preferably 80 mol % or less, particularly preferably 70 mol % or less, and most preferably 60 mol % or less.

Specific examples of repeating units having an acid-decomposable group are shown below, but the present invention is not limited thereto. In the formula, Xa ₁ is any one of H, CH ₃ , CF ₃ and CH ₂ OH, and Rxa and Rxb each represent a linear or branched alkyl group having 1 to 5 carbon atoms.

(Repeating unit having an acid-decomposable group containing an unsaturated bond)
As one aspect of the resin (A), it preferably has a repeating unit having an acid-decomposable group containing an unsaturated bond.
As the repeating unit having an acid-decomposable group containing an unsaturated bond, a repeating unit represented by formula (B) is preferable.

In formula (B),
Xb represents a hydrogen atom, a halogen atom, or an optionally substituted alkyl group.
L represents a single bond or a divalent linking group which may have a substituent.
Ry ₁ to Ry ₃ are each independently a hydrogen atom, a linear or branched alkyl group, a monocyclic or polycyclic cycloalkyl group, an alkenyl group, an alkynyl group, or a monocyclic or polycyclic aryl represents a group. Also, any two of Ry ₁ to Ry ₃ may combine to form a monocyclic or polycyclic group (eg, monocyclic or polycyclic cycloalkyl group, cycloalkenyl group, etc.).
provided that at least one of Ry ₁ to Ry ₃ represents an alkenyl group, an alkynyl group, a monocyclic or polycyclic cycloalkenyl group, or a monocyclic or polycyclic aryl group, or Ry ₁ to Ry ₃ Any two of these combine to form a monocyclic or polycyclic alicyclic ring (eg, monocyclic or polycyclic cycloalkyl group, cycloalkenyl group, etc.). Two or more of Ry ₁ to Ry ₃ are not hydrogen atoms, and when any one of Ry ₁ to Ry ₃ is a hydrogen atom, the other two of Ry ₁ to Ry ₃ are are bonded to each other to form a ring having one or more vinylene groups in the ring structure, and at least one of the vinylene groups is bonded to a hydrogen atom represented by any one of Ry ₁ to Ry ₃ adjacent to the carbon atom that

The alkyl group of Ry ₁ to Ry ₃ is preferably an alkyl group having 1 to 4 carbon atoms such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group and t-butyl group. .
Cycloalkyl groups represented by Ry ₁ to Ry ₃ include monocyclic cycloalkyl groups such as cyclopentyl and cyclohexyl groups, or polycyclic groups such as norbornyl, tetracyclodecanyl, tetracyclododecanyl, and adamantyl groups. is preferred.
The aryl groups represented by Ry ₁ to Ry ₃ are preferably aryl groups having 6 to 15 carbon atoms, more preferably aryl groups having 6 to 10 carbon atoms, such as phenyl, naphthyl and anthryl groups.
A vinyl group is preferable as the alkenyl group for Ry ₁ to Ry ₃ .
An ethynyl group is preferred as the alkynyl group for Ry ₁ to Ry ₃ .
As the cycloalkenyl groups represented by Ry ₁ to Ry ₃ , monocyclic cycloalkyl groups such as cyclopentyl and cyclohexyl groups having a structure partially containing a double bond are preferred.
The cycloalkyl group formed by combining two of Ry ₁ to Ry ₃ is preferably a monocyclic cycloalkyl group such as a cyclopentyl group and a cyclohexyl group. A polycyclic cycloalkyl group such as a cyclododecanyl group and an adamantyl group is preferred. Among them, monocyclic cycloalkyl groups having 5 to 6 carbon atoms are preferred.
In the cycloalkyl group and cycloalkenyl group formed by combining two of Ry ₁ to Ry ₃ , for example, one of the methylene groups constituting the ring is a hetero atom such as an oxygen atom, a carbonyl group, a —SO ₂ — group , and a group having a heteroatom such as —SO ₃ —, a vinylidene group, or a combination thereof. In addition, in these cycloalkyl groups and cycloalkenyl groups, one or more of the ethylene groups constituting the cycloalkane ring and cycloalkene ring may be replaced with a vinylene group.
A preferred embodiment of the combination of Ry ₁ to Ry ₃ is, for example, that Ry ₁ is a methyl group, an ethyl group, a vinyl group, an allyl group, or an aryl group, and Ry ₂ and Rx ₃ are combined to form the above-mentioned Forming a cycloalkyl group or cycloalkenyl group, and Ry ₁ is a hydrogen atom, and Ry ₂ and Ry ₃ are bonded to each other to form a ring having one or more vinylene groups in the ring structure. and at least one of the vinylene groups is present adjacent to the carbon atom to which the hydrogen atom represented by Ry ₁ is bonded.

When Ry ₁ to Ry ₃ further have a substituent, examples of the substituent include an alkyl group (having 1 to 4 carbon atoms), a halogen atom, a hydroxyl group, an alkoxy group (having 1 to 4 carbon atoms), a carboxyl group, and an alkoxy group. A carbonyl group (having 2 to 6 carbon atoms) and the like can be mentioned. The number of carbon atoms in the substituent is preferably 8 or less.

The optionally substituted alkyl group represented by Xb includes, for example, a methyl group and a group represented by —CH ₂ —R ₁₁ . R ₁₁ represents a halogen atom (such as a fluorine atom), a hydroxyl group, or a monovalent organic group, for example, an alkyl group having 5 or less carbon atoms which may be substituted with a halogen atom, acyl groups having 5 or less carbon atoms, and alkoxy groups having 5 or less carbon atoms which may be substituted with halogen atoms, preferably alkyl groups having 3 or less carbon atoms, and more preferably methyl groups. Xb is preferably a hydrogen atom, a fluorine atom, a methyl group, a trifluoromethyl group, or a hydroxymethyl group.

As the divalent linking group of L, -Rt- group, -CO- group, -COO-Rt- group, -COO-Rt-CO- group, -Rt-CO- group, and -O-Rt- group is mentioned. In the formula, Rt represents an alkylene group, a cycloalkylene group, or an aromatic ring group, preferably an aromatic ring group.
L is preferably -Rt-, -CO-, -COO-Rt-CO- or -Rt-CO-. Rt may have a substituent such as a halogen atom, a hydroxyl group, an alkoxy group, or the like. Aromatic groups are preferred.

When each of the above groups in formula (B) has a substituent, examples of the substituent include an alkyl group (having 1 to 4 carbon atoms), a halogen atom, a hydroxyl group, an alkoxy group (having 1 to 4 carbon atoms), A carboxyl group, an alkoxycarbonyl group (having 2 to 6 carbon atoms), and the like can be mentioned. The number of carbon atoms in the substituent is preferably 8 or less.

As the repeating unit represented by the formula (B), an acid-decomposable (meth)acrylic acid tertiary ester-based repeating unit (Xb represents a hydrogen atom or a methyl group, and L represents a —CO— group. ), an acid-decomposable hydroxystyrene tertiary alkyl ether-based repeating unit (a repeating unit in which Xb represents a hydrogen atom or a methyl group and L represents a phenyl group), or an acid-decomposable styrene carboxylic acid tertiary ester-based repeating unit It is preferably a unit (a repeating unit in which Xb represents a hydrogen atom or a methyl group and L represents a -Rt-CO- group (Rt is an aromatic group)).

The content of the repeating unit having an acid-decomposable group containing an unsaturated bond is preferably 15 mol% or more, more preferably 20 mol% or more, and 30 mol% or more, based on the total repeating units in the resin (A). is more preferred. Moreover, the upper limit thereof is preferably 80 mol % or less, more preferably 70 mol % or less, and particularly preferably 60 mol % or less.

Specific examples of repeating units having acid-decomposable groups containing unsaturated bonds are shown below, but the present invention is not limited thereto.
In the formula, Xb and _L1 have the same meanings as Xb and L in formula (B) above. Ar represents an aromatic ring group. R is a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, an alkenyl group, a hydroxyl group, an alkoxy group, an acyloxy group, a cyano group, a nitro group, an amino group, a halogen atom, an ester group (-OCOR''' or -COOR''': R''' represents an alkyl group having 1 to 20 carbon atoms or a fluorinated alkyl group), or a substituent such as a carboxyl group. R' represents a linear or branched alkyl group, a monocyclic or polycyclic cycloalkyl group, an alkenyl group, an alkynyl group, or a monocyclic or polycyclic aryl group. Q represents a heteroatom such as an oxygen atom, a group having a heteroatom such as a carbonyl group, a —SO ₂ — group and a —SO ₃ — group, a vinylidene group, or a combination thereof. l, n, and m represent integers of 0 or more. The upper limit is not limited, and is, for example, 6 or less, preferably 4 or less.

The resin (A) may contain repeating units other than the repeating units described above.
For example, the resin (A) contains at least one repeating unit selected from the group consisting of Group A below and/or at least one repeating unit selected from the group consisting of Group B below. good too.
Group A: A group consisting of the following repeating units (20) to (29).
(20) a repeating unit having an acid group, described later (21) a repeating unit having a fluorine atom or an iodine atom, described later (22) a repeating unit having a lactone group, a sultone group, or a carbonate group, described later (23) described later a repeating unit (24) having a photoacid-generating group; a repeating unit (25) represented by formula (V-1) or formula (V-2) below; and a repeating unit (25) represented by formula (A), described below. Repeating unit (26) Repeating unit represented by formula (B), described later (27) Repeating unit represented by formula (C), described later (28) Repeating unit represented by formula (D), described later (29) Group B of repeating units represented by formula (E) to be described later: a group consisting of the following repeating units (30) to (32).
(30) A repeating unit having at least one group selected from a lactone group, a sultone group, a carbonate group, a hydroxyl group, a cyano group, and an alkali-soluble group, which will be described later (31) Having an alicyclic hydrocarbon structure, which will be described later , a repeating unit not exhibiting acid decomposability (32) a repeating unit represented by the formula (III) having neither a hydroxyl group nor a cyano group, which will be described later

Resin (A) preferably has an acid group, and preferably contains a repeating unit having an acid group, as described later. The definition of the acid group will be explained later together with preferred embodiments of repeating units having an acid group.

When the resist composition is used as an actinic ray-sensitive or radiation-sensitive resin composition for EUV, the resin (A) preferably has at least one repeating unit selected from the group consisting of Group A above.
Moreover, when the resist composition is used as an actinic ray-sensitive or radiation-sensitive resin composition for EUV, the resin (A) preferably contains at least one of a fluorine atom and an iodine atom. When the resin (A) contains both a fluorine atom and an iodine atom, the resin (A) may have one repeating unit containing both a fluorine atom and an iodine atom, and the resin (A) It may contain two types of a repeating unit containing a fluorine atom and a repeating unit containing an iodine atom.
Moreover, when the resist composition is used as an EUV-use actinic ray-sensitive or radiation-sensitive resin composition, the resin (A) preferably has a repeating unit having an aromatic group.
When the resist composition is used as an actinic ray-sensitive or radiation-sensitive resin composition for ArF, the resin (A) preferably has at least one repeating unit selected from the group consisting of Group B above.
When the resist composition is used as an actinic ray-sensitive or radiation-sensitive resin composition for ArF, the resin (A) preferably contains neither fluorine atoms nor silicon atoms.
Moreover, when the resist composition is used as an actinic ray-sensitive or radiation-sensitive resin composition for ArF, the resin (A) preferably does not have an aromatic group.

<Repeating unit having an acid group>
Resin (A) preferably has a repeating unit having an acid group.
As the acid group, an acid group having a pKa of 13 or less is preferable. As described above, the acid dissociation constant of the acid group is preferably 13 or less, more preferably 3-13, and even more preferably 5-10.
When the resin (A) has an acid group with a pKa of 13 or less, the content of the acid group in the resin (A) is not particularly limited, but is often 0.2 to 6.0 mmol/g. Among them, 0.8 to 6.0 mmol/g is preferable, 1.2 to 5.0 mmol/g is more preferable, and 1.6 to 4.0 mmol/g is even more preferable. If the content of the acid group is within the above range, the development proceeds satisfactorily, the formed pattern shape is excellent, and the resolution is also excellent.
The acid group is preferably, for example, a carboxyl group, a hydroxyl group, a phenolic hydroxyl group, a fluorinated alcohol group (preferably a hexafluoroisopropanol group), a sulfonic acid group, a sulfonamide group, or an isopropanol group.
In the hexafluoroisopropanol group, one or more (preferably 1 to 2) fluorine atoms may be substituted with a group other than a fluorine atom (such as an alkoxycarbonyl group). —C(CF ₃ )(OH)—CF ₂ — thus formed is also preferred as an acid group. Also, one or more of the fluorine atoms may be substituted with a group other than a fluorine atom to form a ring containing -C(CF ₃ )(OH)-CF ₂ -.
The repeating unit having an acid group is a repeating unit having a structure in which the polar group is protected by a leaving group that leaves under the action of an acid, and a repeating unit having a lactone group, a sultone group, or a carbonate group, which will be described later. are preferably different repeating units.

A repeating unit having an acid group may have a fluorine atom or an iodine atom.

As the repeating unit having an acid group, a repeating unit represented by formula (B) is preferred.

_R3 represents a hydrogen atom or a monovalent organic group optionally having a fluorine atom or an iodine atom.
As the monovalent organic group optionally having a fluorine atom or an iodine atom, a group represented by -L ₄ -R ₈ is preferred. _L4 represents a single bond or an ester group. R ₈ is an alkyl group optionally having a fluorine atom or an iodine atom, a cycloalkyl group optionally having a fluorine atom or an iodine atom, an aryl group optionally having a fluorine atom or an iodine atom, or a group obtained by combining these.

_R4 and _R5 each independently represent a hydrogen atom, a fluorine atom, an iodine atom, or an alkyl group optionally having a fluorine atom or an iodine atom.

L ₂ is a single bond, an ester group, or —CO—, —O—, or an alkylene group (preferably having 1 to 6 carbon atoms; it may be linear or branched; and —CH ₂ — is a halogen It may be substituted with an atom.) represents a divalent group formed by combining.
L ₃ represents an (n+m+1)-valent aromatic hydrocarbon ring group or an (n+m+1)-valent alicyclic hydrocarbon ring group. Aromatic hydrocarbon ring groups include benzene ring groups and naphthalene ring groups. The alicyclic hydrocarbon ring group may be monocyclic or polycyclic, and examples thereof include cycloalkyl ring groups, norbornene ring groups, and adamantane ring groups.

_R6 represents a hydroxyl group or a fluorinated alcohol group. The fluorinated alcohol group is preferably a monovalent group represented by the following formula (3L).
*-L _6X -R _6X (3L)
_L6X represents a single bond or a divalent linking group. The divalent linking group is not particularly limited, and examples thereof include -CO-, -O-, -SO-, -SO ₂ -, -NR ^A -, alkylene groups (preferably having 1 to 6 carbon atoms, linear or a branched chain), and a divalent linking group combining a plurality of these. ^RA includes a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. Moreover, the said alkylene group may have a substituent. Examples of substituents include halogen atoms (preferably fluorine atoms) and hydroxyl groups. _R6X represents a hexafluoroisopropanol group. When R ₆ is a hydroxyl group, L ₃ is also preferably an (n+m+1)-valent aromatic hydrocarbon ring group.

_R7 represents a halogen atom. A halogen atom includes a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom.
m represents an integer of 1 or more. m is preferably an integer of 1-3, more preferably an integer of 1-2.
n represents an integer of 0 or 1 or more. n is preferably an integer of 1-4.
(n+m+1) is preferably an integer of 1-5.

Repeating units having an acid group include the following repeating units.

A repeating unit represented by the following formula (I) is also preferable as the repeating unit having an acid group.

In formula (I),
R ₄₁ , R ₄₂ and R ₄₃ each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, a halogen atom, a cyano group or an alkoxycarbonyl group. However, _R42 may combine with _Ar4 to form a ring, in which case _R42 represents a single bond or an alkylene group.
X ₄ represents a single bond, -COO- or -CONR ₆₄ -, and R ₆₄ represents a hydrogen atom or an alkyl group.
_L4 represents a single bond or an alkylene group.
Ar ₄ represents an (n+1)-valent aromatic ring group, and when combined with R ₄₂ to form a ring, represents an (n+2)-valent aromatic ring group.
n represents an integer of 1 to 5;

The alkyl groups for R ₄₁ , R ₄₂ and R ₄₃ in formula (I) include methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, sec-butyl group, hexyl group, 2-ethylhexyl group, An alkyl group having 20 or less carbon atoms such as an octyl group and a dodecyl group is preferable, an alkyl group having 8 or less carbon atoms is more preferable, and an alkyl group having 3 or less carbon atoms is even more preferable.

Cycloalkyl groups for R ₄₁ , R ₄₂ and R ₄₃ in formula (I) may be monocyclic or polycyclic. Among them, monocyclic cycloalkyl groups having 3 to 8 carbon atoms such as cyclopropyl group, cyclopentyl group and cyclohexyl group are preferable.
The halogen atoms of R ₄₁ , R ₄₂ and R ₄₃ in formula (I) include fluorine, chlorine, bromine and iodine atoms, preferably fluorine atom.
As the alkyl group contained in the alkoxycarbonyl group of R ₄₁ , R ₄₂ and R ₄₃ in formula (I), the same alkyl groups as those of R ₄₁ , R ₄₂ and R ₄₃ are preferred.

Preferable substituents for the above groups include, for example, an alkyl group, a cycloalkyl group, an aryl group, an amino group, an amido group, a ureido group, a urethane group, a hydroxyl group, a carboxyl group, a halogen atom, an alkoxy group, a thioether group, and an acyl group. , acyloxy groups, alkoxycarbonyl groups, cyano groups, and nitro groups. The number of carbon atoms in the substituent is preferably 8 or less.

Ar ₄ represents an (n+1)-valent aromatic ring group. The divalent aromatic ring group when n is 1 is, for example, a phenylene group, a tolylene group, a naphthylene group, and an arylene group having 6 to 18 carbon atoms such as an anthracenylene group, or a thiophene ring, a furan ring, a pyrrole ring, A divalent aromatic ring group containing a hetero ring such as a benzothiophene ring, a benzofuran ring, a benzopyrrole ring, a triazine ring, an imidazole ring, a benzimidazole ring, a triazole ring, a thiadiazole ring, and a thiazole ring is preferred. In addition, the said aromatic ring group may have a substituent.

Specific examples of the (n+1)-valent aromatic ring group where n is an integer of 2 or more include the above specific examples of the divalent aromatic ring group, with (n−1) any hydrogen atoms removed. A group formed by
The (n+1)-valent aromatic ring group may further have a substituent.

Examples of substituents that the alkyl group, cycloalkyl group, alkoxycarbonyl group, alkylene group, and (n+1)-valent aromatic ring group described above may have include R ₄₁ , R ₄₂ , and R ₄₃ in formula (I). alkoxy groups such as the alkyl groups, methoxy groups, ethoxy groups, hydroxyethoxy groups, propoxy groups, hydroxypropoxy groups, and butoxy groups mentioned in 1 above; aryl groups such as phenyl groups;
The alkyl group for R ₆₄ in —CONR ₆₄ — (R ₆₄ represents a hydrogen atom or an alkyl group) represented by X ₄ includes methyl, ethyl, propyl, isopropyl, n-butyl, sec -butyl, hexyl, 2-ethylhexyl, octyl, dodecyl, and other alkyl groups having 20 or less carbon atoms, preferably alkyl groups having 8 or less carbon atoms.
X ₄ is preferably a single bond, -COO- or -CONH-, more preferably a single bond or -COO-.

The alkylene group for _L4 is preferably an alkylene group having 1 to 8 carbon atoms such as a methylene group, ethylene group, propylene group, butylene group, hexylene group and octylene group.
Ar ₄ is preferably an aromatic ring group having 6 to 18 carbon atoms, more preferably a benzene ring group, a naphthalene ring group, or a biphenylene ring group.
The repeating unit represented by formula (I) preferably has a hydroxystyrene structure. That is, Ar ₄ is preferably a benzene ring group.

As the repeating unit represented by formula (I), a repeating unit represented by the following formula (1) is preferable.

In formula (1),
A represents a hydrogen atom, an alkyl group, a cycloalkyl group, a halogen atom, or a cyano group.
R represents a halogen atom, an alkyl group, a cycloalkyl group, an aryl group, an alkenyl group, an aralkyl group, an alkoxy group, an alkylcarbonyloxy group, an alkylsulfonyloxy group, an alkyloxycarbonyl group or an aryloxycarbonyl group; They may be the same or different depending on the case. When it has a plurality of R, they may jointly form a ring. A hydrogen atom is preferred as R.
a represents an integer of 1 to 3;
b represents an integer from 0 to (5-a).

Examples of repeating units having an acid group are shown below. In the formula, a represents 1 or 2.

Among the above repeating units, repeating units specifically described below are preferable. In the formula, R represents a hydrogen atom or a methyl group, and a represents 2 or 3.

The content of repeating units having an acid group is preferably 10 mol % or more, more preferably 15 mol % or more, relative to all repeating units in the resin (A). Moreover, the upper limit thereof is preferably 70 mol % or less, more preferably 65 mol % or less, and even more preferably 60 mol % or less.

<Repeating Unit Having Fluorine Atom or Iodine Atom>
The resin (A) may have a repeating unit having a fluorine atom or an iodine atom in addition to the <repeating unit having an acid-decomposable group> and the <repeating unit having an acid group> described above. In addition, the <repeating unit having a fluorine atom or an iodine atom> as used herein refers to <repeating units having a lactone group, a sultone group, or a carbonate group> and <repeating units having a photoacid-generating group> described below. It is preferably different from other types of repeating units belonging to group A.

As the repeating unit having a fluorine atom or an iodine atom, a repeating unit represented by formula (C) is preferable.

_L5 represents a single bond or an ester group.
_R9 represents a hydrogen atom or an alkyl group optionally having a fluorine atom or an iodine atom.
R ₁₀ may have a hydrogen atom, an alkyl group optionally having a fluorine atom or an iodine atom, a cycloalkyl group optionally having a fluorine atom or an iodine atom, a fluorine atom or an iodine atom represents an aryl group or a group combining these;

Examples of repeating units having a fluorine atom or an iodine atom are shown below.

The content of repeating units having a fluorine atom or an iodine atom is preferably 0 mol % or more, more preferably 5 mol % or more, and even more preferably 10 mol % or more, relative to all repeating units in the resin (A). Moreover, the upper limit thereof is preferably 50 mol % or less, more preferably 45 mol % or less, and even more preferably 40 mol % or less.
As described above, the repeating units having a fluorine atom or an iodine atom do not include <repeating units having an acid-decomposable group> and <repeating units having an acid group>. The content of repeating units having atoms also means the content of repeating units having fluorine atoms or iodine atoms excluding <repeating units having an acid-decomposable group> and <repeating units having an acid group>.

Among the repeating units of the resin (A), the total content of repeating units containing at least one of a fluorine atom and an iodine atom is preferably 10 mol% or more, more preferably 20 mol%, based on the total repeating units of the resin (A). The above is more preferable, 30 mol % or more is still more preferable, and 40 mol % or more is particularly preferable. Although the upper limit is not particularly limited, it is, for example, 100 mol % or less.
The repeating unit containing at least one of a fluorine atom and an iodine atom includes, for example, a repeating unit having a fluorine atom or an iodine atom and having an acid-decomposable group, a fluorine atom or an iodine atom, and Examples thereof include repeating units having an acid group and repeating units having a fluorine atom or an iodine atom.

<Repeating unit having lactone group, sultone group, or carbonate group>
The resin (A) is a repeating unit having at least one selected from the group consisting of a lactone group, a sultone group, and a carbonate group (hereinafter collectively referred to as "a repeating unit having a lactone group, a sultone group, or a carbonate group"). ).
A repeating unit having a lactone group, a sultone group, or a carbonate group preferably does not have an acid group such as a hydroxyl group and a hexafluoropropanol group.

The lactone group or sultone group may have a lactone structure or sultone structure. The lactone structure or sultone structure is preferably a 5- to 7-membered ring lactone structure or a 5- to 7-membered ring sultone structure. Among them, a 5- to 7-membered ring lactone structure in which a bicyclo structure or spiro structure is formed and another ring structure is condensed with another ring structure, or a 5- to 7-membered ring sultone in a form to form a bicyclo structure or spiro structure. More preferably, the structure is condensed with another ring structure.
The resin (A) has a lactone structure represented by any one of the following formulas (LC1-1) to (LC1-21), or any one of the following formulas (SL1-1) to (SL1-3). It is preferable to have a repeating unit having a lactone group or a sultone group obtained by extracting one or more hydrogen atoms from ring member atoms of a sultone structure.
Also, a lactone group or a sultone group may be directly bonded to the main chain. For example, ring member atoms of a lactone group or a sultone group may constitute the main chain of resin (A).

The lactone structure or sultone structure portion may have a substituent (Rb ₂ ). Preferred substituents (Rb ₂ ) include alkyl groups having 1 to 8 carbon atoms, cycloalkyl groups having 4 to 7 carbon atoms, alkoxy groups having 1 to 8 carbon atoms, alkoxycarbonyl groups having 1 to 8 carbon atoms, and carboxyl groups. , a halogen atom, a cyano group, an acid-decomposable group, and the like. n2 represents an integer of 0-4. When n2 is 2 or more, multiple Rb ₂ may be different, and multiple Rb ₂ may combine to form a ring.

A repeating unit having a group having a lactone structure represented by any one of formulas (LC1-1) to (LC1-21) or a sultone structure represented by any one of formulas (SL1-1) to (SL1-3) Examples thereof include repeating units represented by the following formula (AI).

In formula (AI), Rb ₀ represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 4 carbon atoms.
Preferred substituents that the alkyl group of Rb ₀ may have include a hydroxyl group and a halogen atom.
A halogen atom for Rb ₀ includes a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Rb ₀ is preferably a hydrogen atom or a methyl group.
Ab is a single bond, an alkylene group, a divalent linking group having a monocyclic or polycyclic alicyclic hydrocarbon structure, an ether group, an ester group, a carbonyl group, a carboxyl group, or a divalent group combining these show. Among them, a single bond or a linking group represented by -Ab ₁ -CO ₂ - is preferred. Ab ₁ is a linear or branched alkylene group or a monocyclic or polycyclic cycloalkylene group, preferably a methylene group, ethylene group, cyclohexylene group, adamantylene group or norbornylene group.
V is a group obtained by removing one hydrogen atom from a ring member atom of a lactone structure represented by any one of formulas (LC1-1) to (LC1-21), or formulas (SL1-1) to (SL1- 3) represents a group obtained by removing one hydrogen atom from a ring member atom of the sultone structure represented by any one of 3).

When optical isomers are present in repeating units having a lactone group or a sultone group, any optical isomers may be used. Moreover, one optical isomer may be used alone, or a plurality of optical isomers may be mixed and used. When one kind of optical isomer is mainly used, its optical purity (ee) is preferably 90 or more, more preferably 95 or more.

As the carbonate group, a cyclic carbonate group is preferred.
As the repeating unit having a cyclic carbonate group, a repeating unit represented by the following formula (A-1) is preferable.

In formula (A-1), R _A ¹ represents a hydrogen atom, a halogen atom, or a monovalent organic group (preferably a methyl group).
n represents an integer of 0 or more.
R _A ² represents a substituent. When n is 2 or more, a plurality of R _A ² may be the same or different.
A represents a single bond or a divalent linking group. The divalent linking group includes an alkylene group, a divalent linking group having a monocyclic or polycyclic alicyclic hydrocarbon structure, an ether group, an ester group, a carbonyl group, a carboxyl group, or a combination of these. is preferred.
Z represents an atomic group forming a monocyclic or polycyclic ring together with the group represented by -O-CO-O- in the formula.

Examples of repeating units having a lactone group, a sultone group, or a carbonate group are shown below.

The content of repeating units having a lactone group, a sultone group, or a carbonate group is preferably 1 mol% or more, more preferably 5 mol% or more, and 10 mol% or more, based on all repeating units in the resin (A). More preferred. The upper limit is preferably 85 mol% or less, more preferably 80 mol% or less, even more preferably 70 mol% or less, and particularly preferably 60 mol% or less.

<Repeating Unit Having Photoacid-Generating Group>
The resin (A) may have, as a repeating unit other than the above, a repeating unit having a group that generates an acid upon exposure to actinic rays or radiation (hereinafter also referred to as "photoacid-generating group").
In this case, it can be considered that the repeating unit having a photoacid-generating group corresponds to the photoacid-generating agent B described above.
Examples of such repeating units include repeating units represented by the following formula (4).

^R41 represents a hydrogen atom or a methyl group. ^L41 represents a single bond or a divalent linking group. ^L42 represents a divalent linking group. ^R40 represents a structural site that is decomposed by exposure to actinic rays or radiation to generate an acid in the side chain.
Examples of repeating units having a photoacid-generating group are shown below.

In addition, the repeating unit represented by formula (4) includes, for example, repeating units described in paragraphs [0094] to [0105] of JP-A-2014-041327, and International Publication No. 2018/193954. Examples include repeating units described in paragraph [0094].

The content of the repeating unit having a photoacid-generating group is preferably 1 mol % or more, more preferably 5 mol % or more, relative to all repeating units in the resin (A). Moreover, the upper limit thereof is preferably 40 mol % or less, more preferably 35 mol % or less, and even more preferably 30 mol % or less.

<Repeating unit represented by formula (V-1) or formula (V-2) below>
Resin (A) may have a repeating unit represented by the following formula (V-1) or the following formula (V-2).
Repeating units represented by the following formulas (V-1) and (V-2) below are preferably different repeating units from the repeating units described above.

During the ceremony,
R ₆ and R ₇ each independently represent a hydrogen atom, a hydroxyl group, an alkyl group, an alkoxy group, an acyloxy group, a cyano group, a nitro group, an amino group, a halogen atom, an ester group (-OCOR or -COOR: R is the number of carbon atoms; 1 to 6 alkyl groups or fluorinated alkyl groups), or a carboxyl group. The alkyl group is preferably a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms.
_n3 represents an integer of 0-6.
_n4 represents an integer of 0-4.
^X4 is a methylene group, an oxygen atom, or a sulfur atom.
The repeating units represented by formula (V-1) or (V-2) are exemplified below.
Examples of the repeating unit represented by formula (V-1) or (V-2) include repeating units described in paragraph [0100] of WO 2018/193954.

<Repeating unit for reducing the mobility of the main chain>
The resin (A) preferably has a high glass transition temperature (Tg) from the viewpoint of suppressing excessive diffusion of generated acid or pattern collapse during development. Tg is preferably greater than 90°C, more preferably greater than 100°C, even more preferably greater than 110°C, and particularly preferably greater than 125°C. Since an excessively high Tg causes a decrease in the dissolution rate in the developer, the Tg is preferably 400° C. or less, more preferably 350° C. or less.
In addition, in this specification, the glass transition temperature (Tg) of a polymer such as resin (A) is calculated by the following method. First, the Tg of a homopolymer consisting only of each repeating unit contained in the polymer is calculated by the Bicerano method. Hereinafter, the calculated Tg is referred to as "Tg of repeating unit". Next, the mass ratio (%) of each repeating unit to all repeating units in the polymer is calculated. Next, the Fox formula (described in Materials Letters 62 (2008) 3152, etc.) is used to calculate the Tg at each mass ratio, and these are totaled to obtain the Tg (°C) of the polymer.
The Bicerano method is described in Prediction of polymer properties, Marcel Dekker Inc, New York (1993) and others. Calculation of Tg by the Bicerano method can be performed using a polymer physical property estimation software MDL Polymer (MDL Information Systems, Inc.).

In order to increase the Tg of the resin (A) (preferably to make the Tg higher than 90°C), it is preferable to reduce the mobility of the main chain of the resin (A). Methods for reducing the mobility of the main chain of the resin (A) include the following methods (a) to (e).
(a) introduction of bulky substituents into the main chain (b) introduction of multiple substituents into the main chain (c) introduction of substituents that induce interaction between the resin (A) into the vicinity of the main chain ( d) Main Chain Formation in Cyclic Structure (e) Linking of Cyclic Structure to Main Chain The resin (A) preferably has a repeating unit exhibiting a homopolymer Tg of 130° C. or higher.
The type of repeating unit exhibiting a homopolymer Tg of 130° C. or higher is not particularly limited as long as it is a repeating unit having a homopolymer Tg of 130° C. or higher as calculated by the Bicerano method. Depending on the type of functional group in the repeating units represented by the formulas (A) to (E) described below, the homopolymers correspond to repeating units exhibiting a homopolymer Tg of 130° C. or higher.

(Repeating unit represented by formula (A))
A specific example of means for achieving the above (a) is a method of introducing a repeating unit represented by the formula (A) into the resin (A).

Formula (A), _RA represents a group having a polycyclic structure. R _x represents a hydrogen atom, a methyl group, or an ethyl group. A group having a polycyclic structure is a group having multiple ring structures, and the multiple ring structures may or may not be condensed.
Specific examples of the repeating unit represented by formula (A) include those described in paragraphs [0107] to [0119] of WO 2018/193954.

(Repeating unit represented by formula (B))
A specific example of means for achieving the above (b) is a method of introducing a repeating unit represented by the formula (B) into the resin (A).

In formula (B), R _b1 to R _b4 each independently represent a hydrogen atom or an organic group, and at least two or more of R _b1 to R _b4 represent an organic group.
Moreover, when at least one of the organic groups is a group in which a ring structure is directly linked to the main chain in the repeating unit, the type of the other organic group is not particularly limited.
Further, when none of the organic groups is a group in which the ring structure is directly linked to the main chain in the repeating unit, at least two of the organic groups have three or more constituent atoms excluding hydrogen atoms. is a substituent.
Specific examples of the repeating unit represented by formula (B) include those described in paragraphs [0113] to [0115] of WO 2018/193954.

(Repeating unit represented by formula (C))
A specific example of means for achieving the above (c) is a method of introducing a repeating unit represented by the formula (C) into the resin (A).

In formula (C), R _c1 to R _c4 each independently represent a hydrogen atom or an organic group, and at least one of R _c1 to R _c4 is hydrogen bonding hydrogen within 3 atoms from the main chain carbon It is a group having an atom. Above all, it is preferable to have a hydrogen-bonding hydrogen atom within 2 atoms (closer to the main chain side) in order to induce interaction between the main chains of the resin (A).
Specific examples of the repeating unit represented by formula (C) include those described in paragraphs [0119] to [0121] of WO 2018/193954.

(Repeating unit represented by formula (D))
A specific example of means for achieving the above (d) is a method of introducing a repeating unit represented by the formula (D) into the resin (A).

In formula (D), "cylic" represents a group forming a main chain with a cyclic structure. The number of constituent atoms of the ring is not particularly limited.
Specific examples of the repeating unit represented by formula (D) include those described in paragraphs [0126] to [027] of WO 2018/193954.

(Repeating unit represented by formula (E))
A specific example of means for achieving (e) above is a method of introducing a repeating unit represented by the formula (E) into the resin (A).

In formula (E), each Re independently represents a hydrogen atom or an organic group. Examples of organic groups include alkyl groups, cycloalkyl groups, aryl groups, aralkyl groups, alkenyl groups, and the like, which may have substituents.
A "cyclic" is a cyclic group containing the main chain carbon atoms. The number of atoms contained in the cyclic group is not particularly limited.
Specific examples of the repeating unit represented by formula (E) include those described in paragraphs [0131] to [0133] of WO2018/193954.

<Repeating unit having at least one group selected from lactone group, sultone group, carbonate group, hydroxyl group, cyano group, and alkali-soluble group>
The resin (A) may have repeating units having at least one group selected from lactone groups, sultone groups, carbonate groups, hydroxyl groups, cyano groups, and alkali-soluble groups.
Examples of the repeating unit having a lactone group, a sultone group, or a carbonate group that the resin (A) has include the repeating units described in the above <Repeating unit having a lactone group, sultone group, or carbonate group>. The preferable content is also as described in <Repeating unit having lactone group, sultone group, or carbonate group>.

Resin (A) may have a repeating unit having a hydroxyl group or a cyano group. This improves the adhesion to the substrate and the compatibility with the developer.
A repeating unit having a hydroxyl group or a cyano group is preferably a repeating unit having an alicyclic hydrocarbon structure substituted with a hydroxyl group or a cyano group.
A repeating unit having a hydroxyl group or a cyano group preferably does not have an acid-decomposable group. Repeating units having a hydroxyl group or a cyano group include those described in paragraphs [0153] to [0158] of WO2020/004306.

Resin (A) may have a repeating unit having an alkali-soluble group.
The alkali-soluble group includes a carboxyl group, a sulfonamide group, a sulfonylimide group, a bissulphonylimide group, and an aliphatic alcohol substituted with an electron-withdrawing group at the α-position (e.g., a hexafluoroisopropanol group). is preferred. When the resin (A) contains a repeating unit having an alkali-soluble group, the resolution for contact holes is increased. Repeating units having an alkali-soluble group include those described in paragraphs [0085] and [0086] of JP-A-2014-98921.

<Repeating unit having an alicyclic hydrocarbon structure and not exhibiting acid-decomposability>
The resin (A) may have a repeating unit that has an alicyclic hydrocarbon structure and does not show acid decomposability. This can reduce the elution of low-molecular-weight components from the resist film into the immersion liquid during immersion exposure. Examples of such repeating units include repeating units derived from 1-adamantyl (meth)acrylate, diamantyl (meth)acrylate, tricyclodecanyl (meth)acrylate, or cyclohexyl (meth)acrylate.

<Repeating Unit Represented by Formula (III) Having Neither Hydroxyl Group nor Cyano Group>
Resin (A) may have a repeating unit represented by formula (III) that has neither a hydroxyl group nor a cyano group.

In formula (III), _R5 represents a hydrocarbon group having at least one cyclic structure and having neither a hydroxyl group nor a cyano group.
Ra represents a hydrogen atom, an alkyl group or a --CH ₂ --O--Ra ₂ group. In the formula, _Ra2 represents a hydrogen atom, an alkyl group or an acyl group.

The cyclic structure of R ₅ includes monocyclic hydrocarbon groups and polycyclic hydrocarbon groups. Examples of monocyclic hydrocarbon groups include cycloalkyl groups having 3 to 12 carbon atoms (more preferably 3 to 7 carbon atoms) and cycloalkenyl groups having 3 to 12 carbon atoms.
Detailed definitions of each group in formula (III) and specific examples of the repeating unit include those described in paragraphs [0169] to [0173] of WO 2020/004306.

<Other repeating units>
Furthermore, the resin (A) may have repeating units other than the repeating units described above.
For example, the resin (A) has repeating units selected from the group consisting of repeating units having an oxathian ring group, repeating units having an oxazolone ring group, repeating units having a dioxane ring group, and repeating units having a hydantoin ring group. You may have
Such repeating units are exemplified below.

In addition to the above repeating structural units, the resin (A) has various repeating structural units for the purpose of adjusting dry etching resistance, standard developer suitability, substrate adhesion, resist profile, resolution, heat resistance, sensitivity, and the like. You may have

As the resin (A), all repeating units are composed of (meth)acrylate repeating units (especially when the composition is used as an actinic ray-sensitive or radiation-sensitive resin composition for ArF). preferable. In this case, all repeating units may be methacrylate repeating units, all repeating units may be acrylate repeating units, or all repeating units may be methacrylate repeating units and acrylate repeating units. It is preferable that the acrylate type repeating unit is 50 mol % or less of the total repeating units.

Resin (A) can be synthesized according to a conventional method (for example, radical polymerization).
The weight average molecular weight of the resin (A) is preferably 1,000 to 200,000, more preferably 3,000 to 20,000, and even more preferably 5,000 to 15,000, as polystyrene equivalents by GPC method. By setting the weight average molecular weight of the resin (A) to 1,000 to 200,000, the deterioration of heat resistance and dry etching resistance can be further suppressed. In addition, it is possible to further suppress the deterioration of the developability and the deterioration of the film formability due to an increase in viscosity.
The degree of dispersion (molecular weight distribution) of the resin (A) is generally 1 to 5, preferably 1 to 3, more preferably 1.2 to 3.0, and even more preferably 1.2 to 2.0. The smaller the degree of dispersion, the better the resolution and resist shape, the smoother the side walls of the resist pattern, and the better the roughness.

In the resist composition, the content of resin (A) is preferably 50.0 to 99.9% by mass, more preferably 60.0 to 99.0% by mass, based on the total solid content of the composition.
Also, the resin (A) may be used alone or in combination.

[Acid diffusion controller (C)]
The resist composition may contain an acid diffusion controller (C).
The acid diffusion control agent traps the acid generated from the photoacid generator or the like during exposure, and acts as a quencher that suppresses the reaction of the acid-decomposable resin in the unexposed area due to excess generated acid. Examples of acid diffusion control agents include basic compounds (CA), basic compounds (CB) whose basicity is reduced or lost by exposure to actinic rays or radiation, and nitrogen atoms that are eliminated by the action of an acid. A low-molecular-weight compound (CD) having a group, an onium salt compound (CE) having a nitrogen atom in the cation moiety, and the like can be used as the acid diffusion controller.

In addition, an onium salt, which is a relatively weak acid to the photoacid-generating component, can also be used as the acid diffusion control agent.
A photo-acid generator (a specific photo-acid generator and other photo-acid generators are also collectively referred to as a photo-acid-generating component), and generates an acid that is relatively weak to the acid generated from the photo-acid-generating component When the acid generated from the photoacid-generating component by actinic rays or radiation collides with the onium salt having an unreacted weak acid anion, a weak acid is released by salt exchange. yields an onium salt with a strong acid anion. In this process, the strong acid is exchanged for a weak acid with lower catalytic activity, so that the acid is apparently deactivated and the acid diffusion can be controlled.

Compounds represented by the following formulas (d1-1) to (d1-3) are preferable as the onium salt that is relatively weakly acidic with respect to the photoacid-generating component.

wherein R ⁵¹ is an organic group. The number of carbon atoms is preferably 1-30.
Z ^2c is an organic group. The number of carbon atoms in the organic group is preferably 1-30. However, in the organic group represented by Z ^2c , when a carbon atom is adjacent to SO ^3- specified in the formula, this carbon atom (α carbon atom) is a fluorine atom and/or perfluoro does not have an alkyl group; The α carbon atom is other than a ring member atom of a cyclic structure, and is preferably a methylene group. Further, when the β-position atom with respect to SO ₃ ^— in Z ^2c is a carbon atom (β-carbon atom), the β-carbon atom also does not have a fluorine atom and/or a perfluoroalkyl group as a substituent.
R ⁵² is an organic group (such as an alkyl group), Y ³ is —SO ₂ —, a linear, branched or cyclic alkylene group, or an arylene group, and Y ⁴ is —CO— or — SO ₂ —, and Rf is a hydrocarbon group having a fluorine atom (such as a fluoroalkyl group).

Each M ⁺ is independently an ammonium cation, a sulfonium cation, or an iodonium cation. Examples of M ⁺ in formulas (d1-1) to (d1-3) include the organic cations listed in the description of the specific compound (eg, organic cations represented by M ₁₁ ⁺ in formula (Ia-1) above). Available.
As one aspect, these cations preferably have an acid-decomposable group. The acid-decomposable group includes the acid-decomposable group represented by formula (1) and the acid-decomposable group represented by formula (2).

Zwitterions may be used as acid diffusion control agents. The zwitterionic acid diffusion control agent preferably has a carboxylate anion and preferably also has a sulfonium or iodonium cation.

In the resist composition of the present invention, a known acid diffusion control agent can be used as appropriate. For example, paragraphs [0627] to [0664] of US Patent Application Publication No. 2016/0070167A1, paragraphs [0095] to [0187] of US Patent Application Publication No. 2015/0004544A1, US Patent Application Publication No. 2016/0237190A1. Known compounds disclosed in paragraphs [0403] to [0423] of the specification and paragraphs [0259] to [0328] of US Patent Application Publication No. 2016/0274458A1 can be suitably used as acid diffusion control agents.
Further, for example, specific examples of the basic compound (CA) include those described in paragraphs [0132] to [0136] of WO2020/066824. Specific examples of the basic compound (CB) that reduces or disappears include those described in paragraphs [0137] to [0155] of WO 2020/066824, having a nitrogen atom and an acid Specific examples of the low-molecular-weight compound (CD) having a group that leaves by action include those described in paragraphs [0156] to [0163] of WO2020/066824, and a nitrogen atom in the cation moiety. As specific examples of the onium salt compound (CE) having

When the resist composition contains an acid diffusion control agent, the content of the acid diffusion control agent (the total if multiple types are present) is 0.1 to 11.0 mass based on the total solid content of the composition. %, more preferably 0.1 to 10.0% by mass, still more preferably 0.1 to 8.0% by mass, and particularly preferably 0.1 to 4.0% by mass.
In the resist composition, the acid diffusion controller may be used singly or in combination of two or more.

[Hydrophobic resin (D)]
The resist composition may contain, apart from the resin (A), a hydrophobic resin different from the resin (A).
The hydrophobic resin is preferably designed to be unevenly distributed on the surface of the resist film. may not contribute to
Effects of the addition of the hydrophobic resin include control of the static and dynamic contact angles of the resist film surface with respect to water, suppression of outgassing, and the like.

The hydrophobic resin has one or more of "fluorine atoms", "silicon atoms", and " _CH3 partial structure contained in the side chain portion of the resin" from the viewpoint of uneven distribution on the film surface layer. is preferred, and having two or more is more preferred. Moreover, the hydrophobic resin preferably has a hydrocarbon group having 5 or more carbon atoms. These groups may be present in the main chain of the resin or may be substituted on the side chain.
Hydrophobic resins include compounds described in paragraphs [0275] to [0279] of WO2020/004306.

When the resist composition contains a hydrophobic resin, the content of the hydrophobic resin is preferably 0.01 to 20% by mass, more preferably 0.1 to 15% by mass, based on the total solid content of the resist composition. , more preferably 0.1 to 10% by mass, particularly preferably 0.1 to 5.0% by mass.

[Surfactant (E)]
The resist composition may contain a surfactant. When a surfactant is contained, the adhesion is better and a pattern with fewer development defects can be formed.
The surfactant is preferably a fluorine-based and/or silicon-based surfactant.
As fluorine-based and/or silicon-based surfactants, for example, surfactants disclosed in paragraphs [0218] and [0219] of WO2018/19395 can be used.

One of these surfactants may be used alone, or two or more thereof may be used.

When the resist composition contains a surfactant, the surfactant content is preferably 0.0001 to 2% by mass, more preferably 0.0005 to 1% by mass, based on the total solid content of the composition.

[Solvent (F)]
The resist composition may contain a solvent.
Solvent consists of (M1) propylene glycol monoalkyl ether carboxylate and (M2) propylene glycol monoalkyl ether, lactate, acetate, alkoxypropionate, linear ketone, cyclic ketone, lactone, and alkylene carbonate. It preferably contains at least one selected from the group. This solvent may further contain components other than components (M1) and (M2).

The present inventors have found that the use of such a solvent in combination with the resin described above improves the coatability of the composition and enables the formation of a pattern with fewer development defects. Although the reason for this is not necessarily clear, these solvents have a good balance of the solubility, boiling point, and viscosity of the resins described above, so that unevenness in the film thickness of the composition film and generation of precipitates during spin coating can be suppressed. The inventors believe that this is due to
Details of component (M1) and component (M2) are described in paragraphs [0218] to [0226] of WO2020/004306.

When the solvent further contains components other than components (M1) and (M2), the content of components other than components (M1) and (M2) is preferably 5 to 30% by mass relative to the total amount of the solvent.

The content of the solvent in the resist composition is preferably determined so that the solid content concentration is 0.5 to 30% by mass, more preferably 1 to 20% by mass. By doing so, the coatability of the resist composition can be further improved.
In addition, solid content means all the components other than a solvent.

[Other additives]
The resist composition contains a dissolution inhibiting compound, a dye, a plasticizer, a photosensitizer, a light absorber, and/or a compound that promotes solubility in a developer (for example, a phenol compound having a molecular weight of 1000 or less, or a carboxylic acid alicyclic or aliphatic compounds containing groups).

The resist composition may further comprise a dissolution inhibiting compound. The term "dissolution inhibiting compound" as used herein means a compound having a molecular weight of 3000 or less, which is decomposed by the action of an acid to reduce its solubility in an organic developer.

The resist composition of the present invention is suitably used as a photosensitive composition for EUV light.
EUV light has a wavelength of 13.5 nm, which is shorter than ArF (wavelength 193 nm) light and the like, so the number of incident photons is smaller when exposed with the same sensitivity. Therefore, the influence of "photon shot noise", in which the number of photons stochastically varies, is large, leading to deterioration of LER and bridge defects. To reduce the photon shot noise, there is a method of increasing the number of incident photons by increasing the amount of exposure, but this is a trade-off with the demand for higher sensitivity.

When the A value obtained by the following formula (1) is high, the EUV light and electron beam absorption efficiency of the resist film formed from the resist composition increases, which is effective in reducing photon shot noise. The A value represents the absorption efficiency of the EUV light and the electron beam relative to the mass ratio of the resist film.
Formula (1): A = ([H] x 0.04 + [C] x 1.0 + [N] x 2.1 + [O] x 3.6 + [F] x 5.6 + [S] x 1.5 + [I] × 39.5) / ([H] × 1 + [C] × 12 + [N] × 14 + [O] × 16 + [F] × 19 + [S] × 32 + [I] × 127)
The A value is preferably 0.120 or more. The upper limit is not particularly limited, but if the A value is too large, the EUV light and electron beam transmittance of the resist film will decrease, the optical image profile in the resist film will deteriorate, and as a result, it will be difficult to obtain a good pattern shape. Therefore, 0.240 or less is preferable, and 0.220 or less is more preferable.

In the formula (1), [H] represents the molar ratio of hydrogen atoms derived from the total solid content to the total atoms of the total solid content in the actinic ray-sensitive or radiation-sensitive resin composition, and [C] represents the molar ratio of carbon atoms derived from the total solid content to the total atoms of the total solid content in the actinic ray-sensitive or radiation-sensitive resin composition, [N] is the actinic ray-sensitive or radiation-sensitive resin Represents the molar ratio of nitrogen atoms derived from the total solid content with respect to the total atoms of the total solid content in the composition, [O] is the total atoms of the total solid content in the actinic ray-sensitive or radiation-sensitive resin composition , represents the molar ratio of oxygen atoms derived from the total solid content, and [F] represents the molar ratio of fluorine atoms derived from the total solid content to the total atoms of the total solid content in the actinic ray-sensitive or radiation-sensitive resin composition. represents, [S] represents the molar ratio of sulfur atoms derived from the total solid content to the total atoms of the total solid content in the actinic ray-sensitive or radiation-sensitive resin composition, [I] is the actinic ray-sensitive represents the molar ratio of iodine atoms derived from the total solid content to the total atoms of the total solid content in the curable or radiation-sensitive resin composition.
For example, when the resist composition contains a resin whose polarity increases under the action of acid (acid-decomposable resin), a photoacid generator, an acid diffusion controller, and a solvent, the resin, the photoacid generator, and the acid A diffusion control agent corresponds to solid content. That is, the total atoms of the total solid content correspond to the sum of all atoms derived from the resin, all atoms derived from the photoacid generator, and all atoms derived from the acid diffusion control agent. For example, [H] represents the molar ratio of hydrogen atoms derived from the total solid content to the total atoms of the total solid content. Hydrogen atoms derived from the resin, hydrogen atoms derived from the photo-acid generator, and hydrogen derived from the acid diffusion control agent with respect to the sum of all atoms derived from the acid generator and all atoms derived from the acid diffusion control agent It will represent the total molar ratio of the atoms.

The A value can be calculated by calculating the atomic number ratio when the structures and contents of the constituent components of the total solid content in the resist composition are known. Further, even if the constituent components are unknown, the constituent atomic number ratio can be calculated by analytical methods such as elemental analysis for the resist film obtained by evaporating the solvent component of the resist composition. .

[Resist film, pattern forming method]
Although the procedure of the pattern forming method using the resist composition is not particularly limited, it preferably includes the following steps.
Step 1: Step of forming a resist film on the substrate using the resist composition Step 2: Step of exposing the resist film Step 3: Step of developing the exposed resist film using a developer Below, each of the above The procedure of the process will be detailed.

<Step 1: Resist film forming step>
Step 1 is a step of forming a resist film on a substrate using a resist composition.
The definition of the resist composition is as described above.

A method of forming a resist film on a substrate using a resist composition includes, for example, a method of coating the substrate with the resist composition.
In addition, it is preferable to filter the resist composition before application, if necessary. The pore size of the filter is preferably 0.1 µm or less, more preferably 0.05 µm or less, and even more preferably 0.03 µm or less. Moreover, the filter is preferably made of polytetrafluoroethylene, polyethylene, or nylon.

The resist composition can be applied onto substrates such as those used in the manufacture of integrated circuit devices (eg, silicon, silicon dioxide coatings) by a suitable coating method such as a spinner or coater. The coating method is preferably spin coating using a spinner. The rotation speed for spin coating using a spinner is preferably 1000 to 3000 rpm.
After coating the resist composition, the substrate may be dried to form a resist film. If necessary, various base films (inorganic film, organic film, antireflection film) may be formed under the resist film.

Examples of the drying method include a method of drying by heating. Heating can be carried out by a means provided in a normal exposure machine and/or a developing machine, and may be carried out using a hot plate or the like. The heating temperature is preferably 80 to 150°C, more preferably 80 to 140°C, even more preferably 80 to 130°C. The heating time is preferably 30 to 1000 seconds, more preferably 60 to 800 seconds, even more preferably 60 to 600 seconds.

Although the film thickness of the resist film is not particularly limited, it is preferably 10 to 120 nm from the viewpoint of forming a finer pattern with higher precision. In particular, when EUV exposure is used, the film thickness of the resist film is more preferably 10 to 65 nm, and even more preferably 15 to 50 nm. In the case of ArF liquid immersion exposure, the film thickness of the resist film is more preferably 10 to 120 nm, still more preferably 15 to 90 nm.

A topcoat composition may be used to form a topcoat on the upper layer of the resist film.
It is preferable that the topcoat composition does not mix with the resist film and can be uniformly coated on the upper layer of the resist film. The topcoat is not particularly limited, and a conventionally known topcoat can be formed by a conventionally known method. can be formed.
For example, it is preferable to form a top coat containing a basic compound as described in JP-A-2013-61648 on the resist film. Specific examples of basic compounds that the topcoat may contain include basic compounds that the resist composition may contain.
Also, the topcoat preferably contains a compound containing at least one group or bond selected from the group consisting of an ether bond, a thioether bond, a hydroxyl group, a thiol group, a carbonyl bond, and an ester bond.

<Step 2: Exposure step>
Step 2 is a step of exposing the resist film.
Examples of the exposure method include a method of irradiating the formed resist film with actinic rays or radiation through a predetermined mask.
Actinic rays or radiation include infrared light, visible light, ultraviolet light, far ultraviolet light, extreme ultraviolet light, X-rays, and electron beams, preferably 250 nm or less, more preferably 220 nm or less, particularly preferably 1 -200 nm wavelength deep UV light, specifically KrF excimer laser (248 nm), ArF excimer laser (193 nm), _F2 excimer laser (157 nm), EUV (13 nm), X-rays, and electron beams .

After exposure, baking (heating) is preferably performed before development. Baking accelerates the reaction in the exposed area, resulting in better sensitivity and pattern shape.
The heating temperature is preferably 80 to 150°C, more preferably 80 to 140°C, even more preferably 80 to 130°C.
The heating time is preferably 10 to 1000 seconds, more preferably 10 to 180 seconds, even more preferably 30 to 120 seconds.
Heating can be carried out by a means provided in a normal exposing machine and/or developing machine, and may be carried out using a hot plate or the like.
This step is also called a post-exposure bake.

<Step 3: Development step>
Step 3 is a step of developing the exposed resist film using a developer to form a pattern.
The developer may be an alkaline developer or a developer containing an organic solvent (hereinafter also referred to as an organic developer).

Examples of the development method include a method in which the substrate is immersed in a tank filled with a developer for a certain period of time (dip method), and a method in which the developer is piled up on the surface of the substrate by surface tension and remains stationary for a certain period of time for development (paddle method). ), a method of spraying the developer onto the surface of the substrate (spray method), and a method of continuously ejecting the developer while scanning the developer ejection nozzle at a constant speed onto the substrate rotating at a constant speed (dynamic dispensing method). is mentioned.
Further, after the step of developing, a step of stopping development may be performed while replacing the solvent with another solvent.
The development time is not particularly limited as long as the resin in the unexposed area is sufficiently dissolved, and is preferably 10 to 300 seconds, more preferably 20 to 120 seconds.
The temperature of the developer is preferably 0 to 50°C, more preferably 15 to 35°C.

An alkaline aqueous solution containing alkali is preferably used as the alkaline developer. Although the type of alkaline aqueous solution is not particularly limited, for example, quaternary ammonium salts represented by tetramethylammonium hydroxide, inorganic alkalis, primary amines, secondary amines, tertiary amines, alcohol amines, or cyclic amines. and an alkaline aqueous solution containing Among them, the alkaline developer is preferably an aqueous solution of a quaternary ammonium salt represented by tetramethylammonium hydroxide (TMAH). Suitable amounts of alcohols, surfactants and the like may be added to the alkaline developer. The alkali concentration of the alkali developer is usually 0.1 to 20 mass %. Further, the pH of the alkaline developer is usually 10.0 to 15.0.

The organic developer is a developer containing at least one organic solvent selected from the group consisting of ketone solvents, ester solvents, alcohol solvents, amide solvents, ether solvents, and hydrocarbon solvents. It is preferable to have

A plurality of the above solvents may be mixed, or may be mixed with a solvent other than the above or water. The water content of the developer as a whole is preferably less than 50% by mass, more preferably less than 20% by mass, even more preferably less than 10% by mass, and particularly preferably substantially free of water.
The content of the organic solvent in the organic developer is preferably 50% by mass or more and 100% by mass or less, more preferably 80% by mass or more and 100% by mass or less, and 90% by mass or more and 100% by mass with respect to the total amount of the developer. The following are more preferable, and 95% by mass or more and 100% by mass or less are particularly preferable.

<Other processes>
The pattern forming method preferably includes a step of washing with a rinse after step 3.

Pure water is an example of the rinse solution used in the rinse step after the step of developing with an alkaline developer. An appropriate amount of surfactant may be added to pure water.
An appropriate amount of surfactant may be added to the rinse solution.

The rinsing liquid used in the rinsing step after the development step using the organic developer is not particularly limited as long as it does not dissolve the pattern, and solutions containing common organic solvents can be used. The rinse liquid contains at least one organic solvent selected from the group consisting of hydrocarbon-based solvents, ketone-based solvents, ester-based solvents, alcohol-based solvents, amide-based solvents, and ether-based solvents. is preferred.

The method of the rinsing step is not particularly limited. For example, a method of continuously discharging the rinsing liquid onto the substrate rotating at a constant speed (rotation coating method), or a method of immersing the substrate in a tank filled with the rinsing liquid for a certain period of time. method (dip method), and method of spraying a rinse liquid onto the substrate surface (spray method).
Moreover, the pattern forming method of the present invention may include a heating step (Post Bake) after the rinsing step. In this step, the developing solution and the rinse solution remaining between the patterns and inside the patterns due to baking are removed. In addition, this process smoothes the resist pattern, and has the effect of improving the roughness of the surface of the pattern. The heating step after the rinsing step is usually carried out at 40 to 250° C. (preferably 90 to 200° C.) for 10 seconds to 3 minutes (preferably 30 seconds to 120 seconds).

Also, the substrate may be etched using the formed pattern as a mask. That is, the pattern formed in step 3 may be used as a mask to process the substrate (or the underlying film and substrate) to form a pattern on the substrate.
The method for processing the substrate (or the underlying film and the substrate) is not particularly limited, but the substrate (or the underlying film and the substrate) is dry-etched using the pattern formed in step 3 as a mask. A method of forming a pattern is preferred. Dry etching is preferably oxygen plasma etching.

Various materials used in the resist composition and the pattern forming method of the present invention (e.g., solvent, developer, rinse, composition for forming an antireflection film, composition for forming a top coat, etc.) contain impurities such as metals. preferably does not contain The content of impurities contained in these materials is preferably 1 mass ppm or less, more preferably 10 mass ppb or less, still more preferably 100 mass ppt or less, particularly preferably 10 mass ppt or less, and most preferably 1 mass ppt or less. Here, examples of metal impurities include Na, K, Ca, Fe, Cu, Mg, Al, Li, Cr, Ni, Sn, Ag, As, Au, Ba, Cd, Co, Pb, Ti, V, W, Zn, and the like.

Methods for removing impurities such as metals from various materials include, for example, filtration using a filter. Details of filtration using a filter are described in paragraph [0321] of WO2020/004306.

In addition, as a method of reducing impurities such as metals contained in various materials, for example, a method of selecting a raw material with a low metal content as a raw material constituting various materials, a method of filtering the raw materials constituting various materials with a filter and a method of performing distillation under conditions in which contamination is suppressed as much as possible by, for example, lining the inside of the apparatus with Teflon (registered trademark).

In addition to filter filtration, impurities may be removed by an adsorbent, or filter filtration and an adsorbent may be used in combination. As the adsorbent, known adsorbents can be used. For example, inorganic adsorbents such as silica gel and zeolite, and organic adsorbents such as activated carbon can be used. In order to reduce impurities such as metals contained in the various materials described above, it is necessary to prevent metal impurities from entering during the manufacturing process. Whether the metal impurities are sufficiently removed from the manufacturing equipment can be confirmed by measuring the content of the metal component contained in the cleaning liquid used for cleaning the manufacturing equipment. The content of the metal component contained in the cleaning solution after use is preferably 100 mass ppt (parts per trillion) or less, more preferably 10 mass ppt or less, and even more preferably 1 mass ppt or less.

Conductive compounds are added to organic treatment liquids such as rinsing liquids in order to prevent damage to chemical piping and various parts (filters, O-rings, tubes, etc.) due to electrostatic charging and subsequent electrostatic discharge. You may The conductive compound is not particularly limited, and examples thereof include methanol. The amount added is not particularly limited, but is preferably 10% by mass or less, more preferably 5% by mass or less, from the viewpoint of maintaining preferable developing properties or rinsing properties.
Examples of chemical pipes include SUS (stainless steel), or antistatic polyethylene, polypropylene, or various pipes coated with fluororesin (polytetrafluoroethylene, perfluoroalkoxy resin, etc.). can be used. Antistatic treated polyethylene, polypropylene, or fluororesin (polytetrafluoroethylene, perfluoroalkoxy resin, etc.) can also be used for filters and O-rings.

[Method for manufacturing electronic device]
The present invention also relates to an electronic device manufacturing method including the pattern forming method described above, and an electronic device manufactured by this manufacturing method.
The electronic device of the present invention is preferably mounted in electric/electronic equipment (household appliances, OA (Office Automation), media-related equipment, optical equipment, communication equipment, etc.).

The present invention will be described in more detail below based on examples. Materials, usage amounts, ratios, processing details, processing procedures, and the like shown in the following examples can be changed as appropriate without departing from the gist of the present invention. Therefore, the scope of the present invention should not be construed to be limited by the examples shown below.

[Various Components of Actinic Ray-Sensitive or Radiation-Sensitive Resin Composition]
[Acid-decomposable resin (resin (A)]
Resins A (Resins A-1 to A-55) shown in Tables 3 and 6 are shown below.
Resins A-1 to A-55 were synthesized according to known methods. Table 1 shows the composition ratio (molar ratio; correspondence from left to right), weight average molecular weight (Mw), and degree of dispersion (Mw/Mn) of each repeating unit shown later.
The weight average molecular weight (Mw) and the degree of dispersion (Mw/Mn) of the resins A-1 to A-55 were measured by GPC (carrier: tetrahydrofuran (THF)) (in terms of polystyrene). Also, the composition ratio (molar ratio) of the resin was measured by ¹³ C-NMR (nuclear magnetic resonance).

The structural formulas of resins A-1 to A-55 shown in Table 1 are shown below.

[Photoacid generator]
<Compounds (I) and (II) (specific compounds), and comparative compounds>
The structures of compounds (I) and (II) (compounds X-1 to X-44) and comparative compounds (compounds Z-1 and Z-2) shown in Tables 3 and 6 are shown below.
Compounds X-1 to X-44 and compounds Z-1 and Z-2 were synthesized according to the method for synthesizing compound X-1 described later.

The comparative compound Z-1 below corresponds to a structure containing an acetal structure that is decomposed by the action of an acid in the linking site linking the anion sites. In addition, Comparative Compound Z-2 below corresponds to a structure that does not contain an acid-decomposable group.

In addition, the numerical values attached to each of the above compounds (I) (compounds X-1 to X-44) and comparative compounds (compounds Z-1 and Z-2) (for example, in the case of compound X-1, from the left -3.41 and -0.24 correspond in order) indicates the acid dissociation constant pKa of the acid generated from each compound by exposure (hereinafter also referred to as "generated acid"). For example, compound X-1 generates an acid having the following structure when two cations are decomposed by exposure. The acid generated from compound X-1 has two acidic sites (proton donor sites) of *—SO ₃ H and *—SO ₂ —NH—CO—* in order from the left. The acid dissociation constants pKa derived from are -3.41 and -0.24. That is, the numerical value attached to each compound indicates the acid dissociation constant pKa derived from each acidic site (proton donor site) of the acid generated from each compound upon exposure.

Specifically, when measuring the acid dissociation constant pKa of the acids generated from compound (I) (compounds X-1 to X-44) and comparative compounds (compounds Z-1 and Z-2), ACD ^{/ Labs} Values based on a database of Hammett's substituent constants and known literature values were calculated using Software Package 1 from Co., Ltd. When pKa could not be calculated by the above method, a value obtained by Gaussian 16 based on DFT (density functional theory) was adopted.

In each of the compounds X-1 to X-18 and X-21 to X-44, the highest numerical value among the numerical values attached to each compound corresponds to the acid dissociation constant a2 derived from the structural site Y. In addition, all numerical values other than the highest numerical value among the numerical values attached to each compound correspond to the acid dissociation constant a1 derived from the structural site X.
In each of the compounds X-19 and X-20, the numerical value attached to each compound corresponds to the acid dissociation constant a1 derived from the structural site X.

(Synthesis Example 1: Synthesis of Compound X-1)

Magnesium (18.0 g) was added to tetrahydrofuran (500 mL) to give a mixture. 4-Bromobenzene trifluoride (151.5 g) was added dropwise to the resulting mixture. The above mixture was then stirred for 1 hour to prepare Grignard reagent A. Thionyl chloride (37.7 g) was added to tetrahydrofuran (500 mL) to give a mixture. The resulting mixture was cooled to 0° C., and the previously prepared Grignard reagent A was added dropwise to the mixture. After the mixture was stirred for 1 hour, 1N hydrochloric acid (600 mL) was added to the mixture while maintaining the temperature of the mixture at 0°C. The reaction product generated in the above mixture was extracted with ethyl acetate (600 mL). The resulting organic phase was washed with saturated aqueous sodium bicarbonate solution (500 mL) and water (500 mL), after which the solvent was evaporated from the organic phase. The resulting concentrate was washed with hexane (300 mL) and filtered to obtain Intermediate A (60 g) as a filtered product (yield 56%).

Intermediate A (30.0 g) was added to a mixture of diphosphorus pentoxide (6.8 g) and methanesulfonic acid (90.8 g). After the resulting mixture was cooled to 10°C, 2,6-dimethylphenol (11.9 g) was added and stirred at 20°C for 30 minutes. The resulting mixture was heated to 50°C and stirred for an additional 3 hours, then water (300 mL) was added dropwise at 20°C or below. Extract with methylene chloride (300 mL), wash the organic layer with water (300 mL), and evaporate the solvent. The concentrate was crystallized with ethyl acetate (300 mL) and filtered to obtain Intermediate B (35 g) (yield 73%).

Tert-butyl-2-bromoacetate (7.9 g), cesium carbonate (18.2 g) and dimethylacetamide (174 g) were added to Intermediate B (20.0 g) and stirred at 40° C. for 2 hours. The resulting mixture was cooled to room temperature, filtered, added with methylene chloride (150 g), and washed twice with 1N hydrochloric acid (100 mL). Further, the organic layer was washed twice with water (100 mL), and then the solvent was distilled off. The concentrate was crystallized with diisopropyl ether (200 mL) and filtered to obtain Intermediate C (19 g) (yield 78%).

Methylene chloride (100 mL) and water (100 mL) were mixed and sodium salt (5.0 g) and Intermediate C (13.7 g) were added. After stirring for 1 hour, the aqueous layer was removed and the organic layer was washed with 0.1N hydrochloric acid (100 mL) and water (100 mL). Evaporation of the solvent gave the product (13.8 g) (yield 90%).

<Photoacid generator B>
The structures of the photoacid generators B (compounds B-1 to B-16) shown in Tables 3 and 6 are shown below.

[Acid diffusion control agent]
The structures of acid diffusion control agents C (compounds C-1 to C-8) shown in Tables 3 and 6 are shown below.

[Hydrophobic resin and topcoat resin]
The hydrophobic resins (D-1 to D-6) shown in Tables 3 and 6 and the topcoat resins (PT-1 to PT-3) shown in Table 7 were synthesized.
Table 2 shows the molar ratio of repeating units in the hydrophobic resins (D-1 to D-6) shown in Tables 3 and 6 and the topcoat resins (PT-1 to PT-3) shown in Table 7, Weight average molecular weight (Mw) and dispersity (Mw/Mn) are shown.
The weight average molecular weight (Mw) and the degree of dispersion (Mw/Mn) of the hydrophobic resins D-1 to D-6 and the topcoat resins PT-1 to PT-3 are determined by GPC (carrier: tetrahydrofuran (THF)). measured (in terms of polystyrene). Also, the composition ratio (molar ratio) of the resin was measured by ¹³ C-NMR (nuclear magnetic resonance).

The structures of the monomers used to synthesize the hydrophobic resins D-1 to D-6 shown in Table 2 and the topcoat resins PT-1 to PT-3 shown in Table 7 are shown below.

[Surfactant]
The surfactants shown in Tables 3 and 6 are shown below.
E-1: Megafac F176 (manufactured by DIC Corporation, fluorine-based surfactant)
E-2: Megafac R08 (manufactured by DIC Corporation, fluorine- and silicon-based surfactant)
E-3: PF656 (manufactured by OMNOVA, fluorine-based surfactant)

〔solvent〕
The solvents shown in Tables 3 and 6 are shown below.
F-1: Propylene glycol monomethyl ether acetate (PGMEA)
F-2: Propylene glycol monomethyl ether (PGME)
F-3: Propylene glycol monoethyl ether (PGEE)
F-4: cyclohexanone F-5: cyclopentanone F-6: 2-heptanone F-7: ethyl lactate F-8: γ-butyrolactone F-9: propylene carbonate

[Preparation and pattern formation of actinic ray-sensitive or radiation-sensitive resin composition: EUV exposure]
[Preparation of actinic ray-sensitive or radiation-sensitive resin composition (1)]
Each component shown in Table 3 was mixed so that the solid content concentration was 2% by mass. Next, the resulting mixture is first filtered through a polyethylene filter with a pore size of 50 nm, then with a nylon filter with a pore size of 10 nm, and finally with a polyethylene filter with a pore size of 5 nm, in order to obtain an actinic ray-sensitive or radiation-sensitive A flexible resin composition (hereinafter also referred to as a resist composition) was prepared. In addition, in a resist composition, solid content means all the components other than the solvent. The resulting resist compositions were used in Examples and Comparative Examples.

[Pattern formation and evaluation]
Using the resist composition prepared as described above, the LWR of the pattern developed under the following conditions was evaluated.
In any test, the resist composition (actinic ray-sensitive or radiation-sensitive resin composition) used for pattern formation was left in an environment at 4 ° C. for 3 months after production. It was used.

<Pattern formation (1): EUV exposure, alkaline aqueous solution development>
An underlayer film forming composition AL412 (manufactured by Brewer Science) was applied onto a silicon wafer and baked at 205° C. for 60 seconds to form an underlayer film having a thickness of 20 nm. A resist composition shown in Table 4 was applied thereon and baked at 100° C. for 60 seconds to form a resist film having a thickness of 30 nm.
Using an EUV exposure apparatus (Exitech, Micro Exposure Tool, NA 0.3, Quadrupol, outer sigma 0.68, inner sigma 0.36), pattern irradiation was performed on the silicon wafer having the obtained resist film. rice field. As the reticle, a mask having a line size of 20 nm and a line:space ratio of 1:1 was used.
The exposed resist film was baked at 90° C. for 60 seconds, developed with a tetramethylammonium hydroxide aqueous solution (2.38 mass %) for 30 seconds, and then rinsed with pure water for 30 seconds. After that, it was spin-dried to obtain a positive pattern.

<<Evaluation of LWR: EUV exposure, alkaline aqueous solution development>>
A line-and-space pattern of 20 nm (1:1) resolved at the optimum exposure dose for resolving a line pattern with an average line width of 20 nm was measured using a length-measuring scanning electron microscope (SEM (Ltd.) When observed from above the pattern using S-9380II)) manufactured by Hitachi, the line width was observed at an arbitrary point, and the measurement variation was evaluated by 3σ. A smaller value indicates better performance. LWR (nm) is preferably 4.5 nm or less, more preferably 3.9 nm or less, and even more preferably 3.6 nm or less. The obtained values of LWR (nm) were classified and evaluated according to the following evaluation criteria. Table 4 shows the results.
“A” LWR value of 3.6 nm or less “B” LWR value of more than 3.6 nm and less than or equal to 3.9 nm “C” LWR value of more than 3.9 nm and less than or equal to 4.1 nm “C-” LWR value of 4 .1 nm or less and 4.5 nm or less "D" LWR value greater than 4.5 nm

Table 4 is shown below.
In Tables 4 and 5, in the "characteristics of specific compound" column, "type of acid-decomposable group" means that the acid-decomposable group in the specific compound is the above-described formula (1) (ester structure) and formula (2) Indicates which structure (acetal structure) it corresponds to. When the structure of the acid-decomposable group does not correspond to any of the structures of formulas (1) and (2) described above, it is indicated as "-".
In addition, in the "Characteristics of specific compound" column, "position of acid-decomposable group" means that the acid-decomposable group in the specific compound has the above formula (1) (ester structure) and formula (2) (acetal structure). In the case of corresponding to any of the structures, it shows at which position of the anion site or the cation site the acid-decomposable group is arranged. "A" indicates that the acid-decomposable group is located at the cationic site, and "B" indicates that it is located at the anionic site. When the acid-decomposable group does not correspond to any of the structures of formulas (1) and (2) described above, it is indicated as "-".
In the column of "characteristics of specific compound", "structure of specific compound" indicates to which structure of compounds (I) and (II) described above the specific compound corresponds.
Further, in the column of "characteristics of specific compound", "type of anion site A ₂ ^- " refers to a case where the specific compound corresponds to the compound (I) described above, and the structure of the anion site A ₂ ^- (BB-1) to (BB-3). When the structure of the anion site A ₂ ^- corresponds to the formulas (BB-1) to (BB-3) described above, it is indicated as "A", and when it does not correspond, it is indicated as "B". When the structure of a specific compound does not correspond to the compound (I) described above, it is indicated as "-".

As shown in the table, it was confirmed that the resist compositions of Examples could form patterns with excellent LWR performance even when used after being stored for a long period of time after production.
Further, when the specific compound contained in the resist composition of the example satisfies the following condition (A) and satisfies two or more of the following conditions (B1) to (B3) (preferably the following condition (B1) When all of (B3) are satisfied), it was confirmed that the LWR performance of the pattern formed when used after long-term storage after production was more excellent.
(A) The type of acid-decomposable group of the specific compound is the structure (ester structure) represented by formula (1) or the structure (acetal structure) represented by formula (2).
(B1) The type of acid-decomposable group of the specific compound is the structure (ester structure) represented by formula (1) described above.
(B2) In the specific compound, an acid-decomposable group is arranged at a cation site.
(B3) The specific compound corresponds to compound (I) described above, and the structure of the anion site A ₂ ^- corresponds to formulas (BB-1) to (BB-3) described above.

The resist composition of the comparative example did not exhibit the desired effect.

<Pattern formation (2): EUV exposure, organic solvent development>
An underlayer film forming composition AL412 (manufactured by Brewer Science) was applied onto a silicon wafer and baked at 205° C. for 60 seconds to form an underlayer film having a thickness of 20 nm. A resist composition shown in Table 5 was applied thereon and baked at 100° C. for 60 seconds to form a resist film having a thickness of 30 nm.
Using an EUV exposure apparatus (Exitech, Micro Exposure Tool, NA 0.3, Quadrupol, outer sigma 0.68, inner sigma 0.36), pattern irradiation was performed on the silicon wafer having the obtained resist film. rice field. As the reticle, a mask having a line size of 20 nm and a line:space ratio of 1:1 was used.
The exposed resist film was baked at 90° C. for 60 seconds, developed with n-butyl acetate for 30 seconds, and spin-dried to obtain a negative pattern.

<<Evaluation of LWR: EUV exposure, organic solvent development>>
The LWR (nm) of the formed pattern was measured by the same method as <<Evaluation of LWR: EUV exposure, alkaline aqueous solution development>>. LWR (nm) is preferably 4.5 nm or less, more preferably 3.9 nm or less, and even more preferably 3.6 nm or less. The obtained values of LWR (nm) were classified and evaluated according to the following evaluation criteria. Table 5 shows the results.
“A” LWR value of 3.6 nm or less “B” LWR value of more than 3.6 nm and less than or equal to 3.9 nm “C” LWR value of more than 3.9 nm and less than or equal to 4.1 nm “C-” LWR value of 4 .1 nm or less and 4.5 nm or less "D" LWR value greater than 4.5 nm

As shown in the table, it was confirmed that the resist compositions of Examples could form patterns with excellent LWR performance even when used after being stored for a long period of time after production.
Further, when the specific compound contained in the resist composition of the example satisfies the following condition (A) and satisfies two or more of the following conditions (B1) to (B3) (preferably the following condition (B1) When all of (B3) are satisfied), it was confirmed that the LWR performance of the pattern formed when used after long-term storage after production was more excellent.
(A) The type of acid-decomposable group of the specific compound is the structure (ester structure) represented by formula (1) or the structure (acetal structure) represented by formula (2).
(B1) The type of acid-decomposable group of the specific compound is the structure (ester structure) represented by formula (1) described above.
(B2) In the specific compound, an acid-decomposable group is arranged at a cation site.
(B3) The specific compound corresponds to compound (I) described above, and the structure of the anion site A ₂ ^- corresponds to formulas (BB-1) to (BB-3) described above.

The resist composition of the comparative example did not exhibit the desired effect.

[Preparation and pattern formation of actinic ray-sensitive or radiation-sensitive resin composition: ArF immersion exposure]
[Preparation of actinic ray-sensitive or radiation-sensitive resin composition (2)]
Each component shown in Table 6 was mixed so that the solid content concentration was 4% by mass. Next, the resulting mixture is first filtered through a polyethylene filter with a pore size of 50 nm, then with a nylon filter with a pore size of 10 nm, and finally with a polyethylene filter with a pore size of 5 nm, in order to obtain an actinic ray-sensitive or radiation-sensitive A flexible resin composition (hereinafter also referred to as a resist composition) was prepared. In addition, in a resist composition, solid content means all the components other than the solvent. The resulting resist compositions were used in Examples and Comparative Examples.

[Preparation of topcoat composition]
Various components contained in the topcoat composition shown in Table 7 are shown below.
<Resin>
Resins PT-1 to PT-3 shown in Table 2 were used as the resins shown in Table 7.
<Additive>
The structures of the additives shown in Table 7 are shown below.

<Surfactant>
The surfactants shown in Table 7 are shown below.
E-3: PF656 (manufactured by OMNOVA, fluorine-based surfactant)

<Solvent>
The solvents shown in Table 7 are shown below.
FT-1: 4-methyl-2-pentanol (MIBC)
FT-2: n-decane FT-3: diisoamyl ether

<Preparation of top coat composition>
Each component shown in Table 7 was mixed so that the solid content concentration was 3% by mass, and then the resulting mixture was filtered first with a polyethylene filter with a pore size of 50 nm, then with a nylon filter with a pore size of 10 nm, Finally, a topcoat composition was prepared by filtering in order through a polyethylene filter with a pore size of 5 nm. In addition, solid content here means all the components other than a solvent. The resulting topcoat composition was used in the examples.

[Pattern formation and evaluation]
Using the resist composition prepared as described above, the LWR of the pattern developed under the following conditions was evaluated.
In any test, the resist composition (actinic ray-sensitive or radiation-sensitive resin composition) used for pattern formation was left in an environment at 4 ° C. for 3 months after production. It was used.

<Pattern formation (3): ArF immersion exposure, alkaline aqueous solution development>
An organic antireflection film forming composition ARC29SR (manufactured by Brewer Science) was applied onto a silicon wafer and baked at 205° C. for 60 seconds to form an antireflection film with a thickness of 98 nm. A resist composition shown in Table 8 was applied thereon and baked at 100° C. for 60 seconds to form a resist film having a thickness of 90 nm. For Examples 3-20 to 3-22, a topcoat film was formed on top of the resist film (types of topcoat compositions used are shown in Table 8). The film thickness of the top coat film was set to 100 nm in all cases.
An ArF excimer laser immersion scanner (manufactured by ASML; XT1700i, NA 1.20, Dipole, outer sigma 0.950, inner sigma 0.890, Y deflection) was applied to the resist film with a line width of 45 nm. It was exposed through a 6% halftone mask with a 1 line and space pattern. Ultrapure water was used as the immersion liquid.
The exposed resist film was baked at 90° C. for 60 seconds, developed with a tetramethylammonium hydroxide aqueous solution (2.38 mass %) for 30 seconds, and then rinsed with pure water for 30 seconds. After that, it was spin-dried to obtain a positive pattern.

<<Evaluation of LWR: ArF immersion exposure, alkaline aqueous solution development>>
A line-and-space pattern of 45 nm (1:1) resolved at the optimum exposure dose for resolving a line pattern with an average line width of 45 nm was measured with a length-measuring scanning electron microscope (SEM (Ltd.) When observed from above the pattern using S-9380II)) manufactured by Hitachi, the line width was observed at an arbitrary point, and the measurement variation was evaluated by 3σ. A smaller value indicates better performance. LWR (nm) is preferably 3.5 nm or less, more preferably 2.9 nm or less, and even more preferably 2.5 nm or less. The obtained values of LWR (nm) were classified and evaluated according to the following evaluation criteria. Table 8 shows the results.
“A” LWR value of 2.5 nm or less “B” LWR value of more than 2.5 nm and less than or equal to 2.9 nm “C” LWR value of more than 2.9 nm and less than or equal to 3.2 nm “C-” LWR value of 3 0.2 nm or less and 3.5 nm or less "D" LWR value greater than 3.5 nm

Table 8 is shown below.
In Tables 8 and 9, in the "characteristics of specific compound" column, "type of acid-decomposable group" means that the acid-decomposable group in the specific compound is the above-described formula (1) (ester structure) and formula (2) Indicates which structure (acetal structure) it corresponds to. When the structure of the acid-decomposable group does not correspond to any of the structures of formulas (1) and (2) described above, it is indicated as "-".
In addition, in the "Characteristics of specific compound" column, "position of acid-decomposable group" means that the acid-decomposable group in the specific compound has the above formula (1) (ester structure) and formula (2) (acetal structure). In the case of corresponding to any of the structures, it shows at which position of the anion site or the cation site the acid-decomposable group is arranged. "A" indicates that the acid-decomposable group is located at the cationic site, and "B" indicates that it is located at the anionic site. When the acid-decomposable group does not correspond to any of the structures of formulas (1) and (2) described above, it is indicated as "-".
In the column of "characteristics of specific compound", "structure of specific compound" indicates to which structure of compounds (I) and (II) described above the specific compound corresponds.
In addition, in the column of "type and characteristic portion of specific compound", "type of anion site A ₂ ^- " refers to the case where the specific compound corresponds to the compound (I) described above and the structure of the anion site A ₂ ^- corresponds to the formulas (BB-1) to (BB-3) described above. When the structure of the anion site A ₂ ^- corresponds to the formulas (BB-1) to (BB-3) described above, it is indicated as "A", and when it does not correspond, it is indicated as "B". When the structure of a specific compound does not correspond to the compound (I) described above, it is indicated as "-".

As shown in the table, it was confirmed that the resist compositions of Examples could form patterns with excellent LWR performance even when used after being stored for a long period of time after production.
Further, when the specific compound contained in the resist composition of the example satisfies the following condition (A) and satisfies two or more of the following conditions (B1) to (B3) (preferably the following condition (B1) When all of (B3) are satisfied), it was confirmed that the LWR performance of the pattern formed when used after long-term storage after production was more excellent.
(A) The type of acid-decomposable group of the specific compound is the structure (ester structure) represented by formula (1) or the structure (acetal structure) represented by formula (2).
(B1) The type of acid-decomposable group of the specific compound is the structure (ester structure) represented by formula (1) described above.
(B2) In the specific compound, an acid-decomposable group is arranged at a cation site.
(B3) The specific compound corresponds to compound (I) described above, and the structure of the anion site A ₂ ^- corresponds to formulas (BB-1) to (BB-3) described above.

The resist composition of the comparative example did not exhibit the desired effect.

<Pattern formation (4): ArF immersion exposure, organic solvent development>
An organic antireflection film forming composition ARC29SR (manufactured by Brewer Science) was applied onto a silicon wafer and baked at 205° C. for 60 seconds to form an antireflection film with a thickness of 98 nm. A resist composition shown in Table 9 was applied thereon and baked at 100° C. for 60 seconds to form a resist film (actinic ray-sensitive or radiation-sensitive film) with a thickness of 90 nm. For Examples 4-20 to 4-22, a topcoat film was formed on top of the resist film (types of topcoat compositions used are shown in Table 9). The film thickness of the top coat film was set to 100 nm in all cases.
An ArF excimer laser immersion scanner (manufactured by ASML; XT1700i, NA 1.20, Dipole, outer sigma 0.950, inner sigma 0.850, Y deflection) was applied to the resist film with a line width of 45 nm. It was exposed through a 6% halftone mask with a 1 line and space pattern. Ultrapure water was used as the immersion liquid.
The exposed resist film was baked at 90° C. for 60 seconds, developed with n-butyl acetate for 30 seconds, and then rinsed with 4-methyl-2-pentanol for 30 seconds. After that, it was spin-dried to obtain a negative pattern.

<<Evaluation of LWR: ArF immersion exposure, organic solvent development>>
The LWR (nm) of the formed pattern was measured by the same method as <<Evaluation of LWR: ArF exposure, alkaline aqueous solution development>>. LWR (nm) is preferably 3.5 nm or less, more preferably 2.9 nm or less, and even more preferably 2.5 nm or less. The obtained values of LWR (nm) were classified and evaluated according to the following evaluation criteria. Table 9 shows the results.
“A” LWR value of 2.5 nm or less “B” LWR value of more than 2.5 nm and less than or equal to 2.9 nm “C” LWR value of more than 2.9 nm and less than or equal to 3.2 nm “C-” LWR value of 3 0.2 nm or less and 3.5 nm or less "D" LWR value greater than 3.5 nm

Table 9 is shown below.

As shown in the table, it was confirmed that the resist compositions of Examples could form patterns with excellent LWR performance even when used after being stored for a long period of time after production.
Further, when the specific compound contained in the resist composition of the example satisfies the following condition (A) and satisfies two or more of the following conditions (B1) to (B3) (preferably the following condition (B1) When all of (B3) are satisfied), it was confirmed that the LWR performance of the pattern formed when used after long-term storage after production was more excellent.
(A) The type of acid-decomposable group of the specific compound is the structure (ester structure) represented by formula (1) or the structure (acetal structure) represented by formula (2).
(B1) The type of acid-decomposable group of the specific compound is the structure (ester structure) represented by formula (1) described above.
(B2) In the specific compound, an acid-decomposable group is arranged at a cation site.
(B3) The specific compound corresponds to compound (I) described above, and the structure of the anion site A ₂ ^- corresponds to formulas (BB-1) to (BB-3) described above.

The resist composition of the comparative example did not exhibit the desired effect.

Claims (9)

containing a resin that decomposes under the action of an acid to increase its polarity, and a compound that generates an acid when exposed to actinic rays or radiation;
An actinic ray- or radiation-sensitive resin composition, wherein the compound that generates an acid upon exposure to actinic rays or radiation comprises any one or more of the following compounds (I) and (II).
Compound (I):
A compound having one or more of the following structural sites X and one or more of the following structural sites Y, and an acid-decomposable group in which a polar group is protected by a leaving group that is released by the action of an acid, A compound that generates an acid containing the following first acidic site derived from the structural site X below and the second acidic site described below derived from the structural site Y below upon irradiation with light or radiation.
Structural site X: Structural site consisting of an anionic site A ₁ ⁻ and a cation site M ₁ ⁺ and forming a first acidic site represented by HA ₁ upon exposure to actinic rays or radiation Structural site Y: Anionic site A ₂ ⁻ and a cation site M ₂ ⁺ and a structural site that forms a second acidic site represented by HA ₂ upon exposure to actinic rays or radiation. meet.
Condition IA: A compound PI obtained by replacing the cation site M ₁ ⁺ in the structural site X and the cation site M ₂ ⁺ in the structural site Y in the compound (I) with H ⁺ is and the acid dissociation constant a1 derived from the acidic site represented by HA ₁ obtained by replacing the cation site M 1 ⁺ with H ⁺ , _and the cation site M ₂ ⁺ in the structural site Y with H ⁺ It has an acid dissociation constant a2 derived from the acidic site represented by _HA2 , and the acid dissociation constant a2 is greater than the acid dissociation constant a1.
Condition IB: The compound (I) links ^an anion site A ₁ - in one or more structural sites X and an anion site A ₂ ^- in one or more structural sites Y by the action of an acid. It is a structure in which the site is not cleaved.
Compound (II):
A compound having two or more structural moieties X, one or more structural moieties Z described below, and an acid-decomposable group in which a polar group is protected by a leaving group that leaves under the action of an acid, A compound that generates an acid containing two or more of the first acidic sites derived from the structural site X and the structural site Z when irradiated with light or radiation.
Structural site Z: nonionic site capable of neutralizing acid provided that compound (II) satisfies the following condition IIB.
Condition IIB: The compound (II) has a structure in which the sites connecting the two or more anion sites A ₁ ^- in the structural sites X and the structural sites Z are not cleaved by the action of an acid. The actinic ray-sensitive or radiation-sensitive resin composition according to claim 1, wherein the acid-decomposable group represents a group represented by the following formula (1) or (2).

In formula (1), R ₁₁ to R ₁₃ each independently represent an alkyl group, a cycloalkyl group, an alkenyl group, or an aryl group. Two of R ₁₁ to R ₁₃ may combine with each other to form a ring. * represents the binding site.
In formula (2), _R2 represents an alkyl group or a cycloalkyl group. _R3 represents a hydrogen atom, an alkyl group, or a cycloalkyl group. In addition, R ₂ and R ₃ may combine with each other to form a ring. * represents the binding site. 3. The actinic ray-sensitive or radiation-sensitive resin composition according to claim 2, wherein said acid-decomposable group represents a group represented by formula (1). In the compound (I), at least one of the cation site M ₁ ⁺ and the cation site M ₂ ⁺ has the acid-decomposable group, and in the compound (II), at least one of the cation site M ₁ ⁺ The actinic ray-sensitive or radiation-sensitive resin composition according to any one of claims 1 to 3, which has the acid-decomposable group. 5. The actinic ray-sensitive or sensitive structure according to any one of claims 1 to 4, wherein the anion site A ₂ ^- represents a structure represented by any one of formulas (BB-1) to (BB-3). A radioactive resin composition.
The actinic ray-sensitive or sensitive according to any one of claims 1 to 5, wherein the anion site A ₁ ^- represents a structure represented by any one of formulas (AA-1) and (AA-3). A radioactive resin composition.
A resist film formed using the actinic ray-sensitive or radiation-sensitive resin composition according to any one of claims 1 to 6. A step of forming a resist film on a substrate using the actinic ray-sensitive or radiation-sensitive resin composition according to any one of claims 1 to 6;
exposing the resist film;
and developing the exposed resist film using a developer. A method for manufacturing an electronic device, comprising the pattern forming method according to claim 8 .